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Stephen Chung 2020-07-10 22:06:02 +08:00
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2
Cargo.toml
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@ -21,7 +21,7 @@ num-traits = { version = "0.2.11", default-features = false }
[features] [features]
#default = ["unchecked", "sync", "no_optimize", "no_float", "only_i32", "no_index", "no_object", "no_function", "no_module"] #default = ["unchecked", "sync", "no_optimize", "no_float", "only_i32", "no_index", "no_object", "no_function", "no_module"]
default = [] default = ["internals"]
plugins = [] plugins = []
unchecked = [] # unchecked arithmetic unchecked = [] # unchecked arithmetic
sync = [] # restrict to only types that implement Send + Sync sync = [] # restrict to only types that implement Send + Sync

3
README.md
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@ -34,7 +34,8 @@ Features
* Rugged - protected against malicious attacks (such as [stack-overflow](https://schungx.github.io/rhai/safety/max-call-stack.html), [over-sized data](https://schungx.github.io/rhai/safety/max-string-size.html), and [runaway scripts](https://schungx.github.io/rhai/safety/max-operations.html) etc.) that may come from untrusted third-party user-land scripts. * Rugged - protected against malicious attacks (such as [stack-overflow](https://schungx.github.io/rhai/safety/max-call-stack.html), [over-sized data](https://schungx.github.io/rhai/safety/max-string-size.html), and [runaway scripts](https://schungx.github.io/rhai/safety/max-operations.html) etc.) that may come from untrusted third-party user-land scripts.
* Track script evaluation [progress](https://schungx.github.io/rhai/safety/progress.html) and manually terminate a script run. * Track script evaluation [progress](https://schungx.github.io/rhai/safety/progress.html) and manually terminate a script run.
* [Function overloading](https://schungx.github.io/rhai/language/overload.html). * [Function overloading](https://schungx.github.io/rhai/language/overload.html).
* [Operator overloading](https://schungx.github.io/rhai/rust/operators.html) and [custom operators](https://schungx.github.io/rhai/engine/custom-op.html). * [Operator overloading](https://schungx.github.io/rhai/rust/operators.html).
* Support for use as a [DSL](https://schungx.github.io/rhai/engine/dsl.html) - [disabling keywords/operators](https://schungx.github.io/rhai/engine/disable.html), [custom operators](https://schungx.github.io/rhai/engine/custom-op.html) and extending the language with [custom syntax](https://schungx.github.io/rhai/engine/custom-syntax.html).
* Dynamic dispatch via [function pointers](https://schungx.github.io/rhai/language/fn-ptr.html). * Dynamic dispatch via [function pointers](https://schungx.github.io/rhai/language/fn-ptr.html).
* Some support for [object-oriented programming (OOP)](https://schungx.github.io/rhai/language/oop.html). * Some support for [object-oriented programming (OOP)](https://schungx.github.io/rhai/language/oop.html).
* Organize code base with dynamically-loadable [modules](https://schungx.github.io/rhai/language/modules.html). * Organize code base with dynamically-loadable [modules](https://schungx.github.io/rhai/language/modules.html).

6
RELEASES.md
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@ -11,6 +11,11 @@ This version adds:
* Ability to define custom operators (which must be valid identifiers). * Ability to define custom operators (which must be valid identifiers).
* Low-level API to register functions. * Low-level API to register functions.
Bug fixes
---------
* Fixed method calls in the middle of a dot chain.
Breaking changes Breaking changes
---------------- ----------------
@ -31,6 +36,7 @@ New features
* The boolean `^` (XOR) operator is added. * The boolean `^` (XOR) operator is added.
* `FnPtr` is exposed as the function pointer type. * `FnPtr` is exposed as the function pointer type.
* `rhai::module_resolvers::ModuleResolversCollection` added to try a list of module resolvers. * `rhai::module_resolvers::ModuleResolversCollection` added to try a list of module resolvers.
* It is now possible to mutate the first argument of a module-qualified function call when the argument is a simple variable (but not a module constant).
Version 0.16.1 Version 0.16.1

8
doc/src/SUMMARY.md
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@ -105,9 +105,11 @@ The Rhai Scripting Language
5. [Volatility Considerations](engine/optimize/volatility.md) 5. [Volatility Considerations](engine/optimize/volatility.md)
6. [Subtle Semantic Changes](engine/optimize/semantics.md) 6. [Subtle Semantic Changes](engine/optimize/semantics.md)
4. [Low-Level API](rust/register-raw.md) 4. [Low-Level API](rust/register-raw.md)
5. [Disable Keywords and/or Operators](engine/disable.md) 5. [Use as DSL](engine/dsl.md)
6. [Custom Operators](engine/custom-op.md) 1. [Disable Keywords and/or Operators](engine/disable.md)
7. [Eval Statement](language/eval.md) 2. [Custom Operators](engine/custom-op.md)
3. [Extending with Custom Syntax](engine/custom-syntax.md)
6. [Eval Statement](language/eval.md)
9. [Appendix](appendix/index.md) 9. [Appendix](appendix/index.md)
1. [Keywords](appendix/keywords.md) 1. [Keywords](appendix/keywords.md)
2. [Operators and Symbols](appendix/operators.md) 2. [Operators and Symbols](appendix/operators.md)

3
doc/src/about/features.md
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@ -67,4 +67,5 @@ Flexible
* Surgically [disable keywords and operators] to restrict the language. * Surgically [disable keywords and operators] to restrict the language.
* [Custom operators]. * Use as a [DSL] by [disabling keywords/operators][disable keywords and operators], [custom operators]
and extending the language with [custom syntax].

1
doc/src/appendix/operators.md
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@ -41,6 +41,7 @@ Symbols
| ------------ | ------------------------ | | ------------ | ------------------------ |
| `:` | Property value separator | | `:` | Property value separator |
| `::` | Module path separator | | `::` | Module path separator |
| `#` | _Reserved_ |
| `=>` | _Reserved_ | | `=>` | _Reserved_ |
| `->` | _Reserved_ | | `->` | _Reserved_ |
| `<-` | _Reserved_ | | `<-` | _Reserved_ |

282
doc/src/engine/custom-syntax.md Normal file
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@ -0,0 +1,282 @@
Extending Rhai with Custom Syntax
================================
{{#include ../links.md}}
For the ultimate advantageous, there is a built-in facility to _extend_ the Rhai language
with custom-defined _syntax_.
But before going off to define the next weird statement type, heed this warning:
Don't Do It™
------------
Stick with standard language syntax as much as possible.
Having to learn Rhai is bad enough, no sane user would ever want to learn _yet_ another
obscure language syntax just to do something.
Try to use [custom operators] first. Defining a custom syntax should be considered a _last resort_.
Where This Might Be Useful
-------------------------
* Where an operation is used a _LOT_ and a custom syntax saves a lot of typing.
* Where a custom syntax _significantly_ simplifies the code and _significantly_ enhances understanding of the code's intent.
* Where certain logic cannot be easily encapsulated inside a function. This is usually the case where _closures_ are required, because Rhai does not have closures.
* Where you just want to confuse your user and make their lives miserable, because you can.
Step One - Start With `internals`
--------------------------------
Since a custom syntax taps deeply into the `AST` and evaluation process of the `Engine`,
the [`internals`] feature must be on in order to expose these necessary internal data structures.
Beware that Rhai internal data structures are _volatile_ and may change without warning.
Caveat emptor.
Step Two - Design The Syntax
---------------------------
A custom syntax is simply a list of symbols.
These symbol types can be used:
* Standard [keywords]({{rootUrl}}/appendix/keywords.md)
* Standard [operators]({{rootUrl}}/appendix/operators.md#operators).
* Reserved [symbols]({{rootUrl}}/appendix/operators.md#symbols).
* Identifiers following the [variable] naming rules.
* `$expr$` - any valid expression, statement or statement block.
* `$block$` - any valid statement block (i.e. must be enclosed by `'{'` .. `'}'`).
* `$ident$` - any [variable] name.
### The First Symbol Must be a Keyword
There is no specific limit on the combination and sequencing of each symbol type,
except the _first_ symbol which must be a [custom keyword].
It _cannot_ be a [built-in keyword]({{rootUrl}}/appendix/keywords.md).
However, it _may_ be a built-in keyword that has been [disabled][disable keywords and operators].
### The First Symbol Must be Unique
Rhai uses the _first_ symbol as a clue to parse custom syntax.
Therefore, at any one time, there can only be _one_ custom syntax starting with each unique symbol.
Any new custom syntax definition using the same first symbol simply _overwrites_ the previous one.
### Example
```rust
exec $ident$ <- $expr$ : $block$
```
The above syntax is made up of a stream of symbols:
| Position | Input | Symbol | Description |
| :------: | :---: | :-------: | -------------------------------------------------------------------------------------------------------- |
| 1 | | `exec` | custom keyword |
| 2 | 1 | `$ident$` | a variable name |
| 3 | | `<-` | the left-arrow symbol (which is a [reserved symbol]({{rootUrl}}/appendix/operators.md#symbols) in Rhai). |
| 4 | 2 | `$expr$` | an expression, which may be enclosed with `{` .. `}`, or not. |
| 5 | | `:` | the colon symbol |
| 6 | 3 | `$block$` | a statement block, which must be enclosed with `{` .. `}`. |
This syntax matches the following sample code and generates three inputs (one for each non-keyword):
```rust
// Assuming the 'exec' custom syntax implementation declares the variable 'hello':
let x = exec hello <- foo(1, 2) : {
hello += bar(hello);
baz(hello);
};
print(x); // variable 'x' has a value returned by the custom syntax
print(hello); // variable declared by a custom syntax persists!
```
Step Three - Implementation
--------------------------
Any custom syntax must include an _implementation_ of it.
### Function Signature
The function signature of an implementation is:
```rust
Fn(
engine: &Engine,
scope: &mut Scope,
mods: &mut Imports,
state: &mut State,
lib: &Module,
this_ptr: &mut Option<&mut Dynamic>,
inputs: &[Expr],
level: usize
) -> Result<Dynamic, Box<EvalAltResult>>
```
where:
* `engine : &Engine` - reference to the current [`Engine`].
* `scope : &mut Scope` - mutable reference to the current [`Scope`]; variables can be added to it.
* `mods : &mut Imports` - mutable reference to the current collection of imported [`Module`]'s; **do not touch**.
* `state : &mut State` - mutable reference to the current evaluation state; **do not touch**.
* `lib : &Module` - reference to the current collection of script-defined functions.
* `this_ptr : &mut Option<&mut Dynamic>` - mutable reference to the current binding of the `this` pointer; **do not touch**.
* `inputs : &[Expr]` - a list of input expression trees.
* `level : usize` - the current function call level.
There are a lot of parameters, most of which should not be touched or Bad Things Happen™.
They represent the running _content_ of a script evaluation and should simply be passed
straight-through the the [`Engine`].
### Access Arguments
The most important argument is `inputs` where the matched identifiers (`$ident$`), expressions/statements (`$expr$`)
and statement blocks (`$block$) are provided.
To access a particular argument, use the following patterns:
| Argument type | Pattern (`n` = slot in `inputs`) | Result type | Description |
| :-----------: | ---------------------------------------- | :---------: | ------------------ |
| `$ident$` | `inputs[n].get_variable_name().unwrap()` | `&str` | name of a variable |
| `$expr$` | `inputs.get(n).unwrap()` | `Expr` | an expression tree |
| `$block$` | `inputs.get(n).unwrap()` | `Expr` | an expression tree |
### Evaluate an Expression Tree
Use the `engine::eval_expression_tree` method to evaluate an expression tree.
```rust
let expr = inputs.get(0).unwrap();
let result = engine.eval_expression_tree(scope, mods, state, lib, this_ptr, expr, level)?;
```
As can be seem above, most arguments are simply passed straight-through to `engine::eval_expression_tree`.
### Declare Variables
New variables maybe declared (usually with a variable name that is passed in via `$ident$).
It can simply be pushed into the [`scope`].
However, beware that all new variables must be declared _prior_ to evaluating any expression tree.
In other words, any `scope.push(...)` calls must come _before_ any `engine::eval_expression_tree(...)` calls.
```rust
let var_name = inputs[0].get_variable_name().unwrap().to_string();
let expr = inputs.get(1).unwrap();
scope.push(var_name, 0 as INT); // do this BEFORE engine.eval_expression_tree!
let result = engine.eval_expression_tree(scope, mods, state, lib, this_ptr, expr, level)?;
```
Step Four - Register the Custom Syntax
-------------------------------------
Use `Engine::register_custom_syntax` to register a custom syntax.
Again, beware that the _first_ symbol must be unique. If there already exists a custom syntax starting
with that symbol, the previous syntax will be overwritten.
The syntax is passed simply as a slice of `&str`.
```rust
// Custom syntax implementation
fn implementation_func(
engine: &Engine,
scope: &mut Scope,
mods: &mut Imports,
state: &mut State,
lib: &Module,
this_ptr: &mut Option<&mut Dynamic>,
inputs: &[Expr],
level: usize
) -> Result<Dynamic, Box<EvalAltResult>> {
let var_name = inputs[0].get_variable_name().unwrap().to_string();
let stmt = inputs.get(1).unwrap();
let condition = inputs.get(2).unwrap();
// Push one new variable into the 'scope' BEFORE 'eval_expression_tree'
scope.push(var_name, 0 as INT);
loop {
// Evaluate the statement block
engine.eval_expression_tree(scope, mods, state, lib, this_ptr, stmt, level)?;
// Evaluate the condition expression
let stop = !engine
.eval_expression_tree(scope, mods, state, lib, this_ptr, condition, level)?
.as_bool()
.map_err(|_| EvalAltResult::ErrorBooleanArgMismatch(
"do-while".into(), expr.position()
))?;
if stop {
break;
}
}
Ok(().into())
}
// Register the custom syntax (sample): do |x| -> { x += 1 } while x < 0;
engine.register_custom_syntax(
&[ "do", "|", "$ident$", "|", "->", "$block$", "while", "$expr$" ], // the custom syntax
1, // the number of new variables declared within this custom syntax
implementation_func
)?;
```
Step Five - Disable Unneeded Statement Types
-------------------------------------------
When a DSL needs a custom syntax, most likely than not it is extremely specialized.
Therefore, many statement types actually may not make sense under the same usage scenario.
So, while at it, better [disable][disable keywords and operators] those built-in keywords
and operators that should not be used by the user. The would leave only the bare minimum
language surface exposed, together with the custom syntax that is tailor-designed for
the scenario.
A keyword or operator that is disabled can still be used in a custom syntax.
In an extreme case, it is possible to disable _every_ keyword in the language, leaving only
custom syntax (plus possibly expressions). But again, Don't Do It™ - unless you are certain
of what you're doing.
Step Six - Document
-------------------
For custom syntax, documentation is crucial.
Make sure there are _lots_ of examples for users to follow.
Step Seven - Profit!
--------------------

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doc/src/engine/dsl.md Normal file
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@ -0,0 +1,84 @@
Use Rhai as a Domain-Specific Language (DSL)
===========================================
{{#include ../links.md}}
Rhai can be successfully used as a domain-specific language (DSL).
Expressions Only
----------------
In many DSL scenarios, only evaluation of expressions is needed.
The `Engine::eval_expression_XXX`[`eval_expression`] API can be used to restrict
a script to expressions only.
Disable Keywords and/or Operators
--------------------------------
In some DSL scenarios, it is necessary to further restrict the language to exclude certain
language features that are not necessary or dangerous to the application.
For example, a DSL may disable the `while` loop altogether while keeping all other statement
types intact.
It is possible, in Rhai, to surgically [disable keywords and operators].
Custom Operators
----------------
On the other hand, some DSL scenarios require special operators that make sense only for
that specific environment. In such cases, it is possible to define [custom operators] in Rhai.
For example:
```rust
let animal = "rabbit";
let food = "carrot";
animal eats food // custom operator - 'eats'
eats(animal, food) // <- the above really de-sugars to this
```
Although a [custom operator] always de-sugars to a simple function call,
nevertheless it makes the DSL syntax much simpler and expressive.
Custom Syntax
-------------
For advanced DSL scenarios, it is possible to define entire expression [_syntax_][custom syntax] -
essentially custom statement types.
The [`internals`] feature is needed to be able to define [custom syntax] in Rhai.
For example, the following is a SQL like syntax for some obscure DSL operation:
```rust
let table = [..., ..., ..., ...];
// Syntax = "calculate" $ident$ $ident$ "from" $expr$ "->" $ident$ ":" $expr$
let total = calculate sum price from table -> row : row.weight > 50;
// Note: There is nothing special about the use of symbols; to make it look exactly like SQL:
// Syntax = "SELECT" $ident$ "(" $ident$ ")" "FROM" $expr$ "AS" $ident$ "WHERE" $expr$
let total = SELECT sum(price) FROM table AS row WHERE row.weight > 50;
```
After registering this custom syntax with Rhai, it can be used anywhere inside a script as
a normal expression.
For its evaluation, the callback function will receive the following list of parameters:
`exprs[0] = "sum"` - math operator
`exprs[1] = "price"` - field name
`exprs[2] = Expr(table)` - data source
`exprs[3] = "row"` - loop variable name
`exprs[4] = Expr(row.wright > 50)` - expression
The other identified, such as `"select"`, `"from"`, as as as symbols `->` and `:` are
parsed in the order defined within the custom syntax.

4
doc/src/language/loop.md
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@ -3,9 +3,9 @@ Infinite `loop`
{{#include ../links.md}} {{#include ../links.md}}
Infinite loops follow C syntax. Infinite loops follow Rust syntax.
Like C, `continue` can be used to skip to the next iteration, by-passing all following statements; Like Rust, `continue` can be used to skip to the next iteration, by-passing all following statements;
`break` can be used to break out of the loop unconditionally. `break` can be used to break out of the loop unconditionally.
```rust ```rust

2
doc/src/links.md
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@ -89,6 +89,7 @@
[`eval`]: {{rootUrl}}/language/eval.md [`eval`]: {{rootUrl}}/language/eval.md
[OOP]: {{rootUrl}}/language/oop.md [OOP]: {{rootUrl}}/language/oop.md
[DSL]: {{rootUrl}}/engine/dsl.md
[maximum statement depth]: {{rootUrl}}/safety/max-stmt-depth.md [maximum statement depth]: {{rootUrl}}/safety/max-stmt-depth.md
[maximum call stack depth]: {{rootUrl}}/safety/max-call-stack.md [maximum call stack depth]: {{rootUrl}}/safety/max-call-stack.md
@ -107,3 +108,4 @@
[disable keywords and operators]: {{rootUrl}}/engine/disable.md [disable keywords and operators]: {{rootUrl}}/engine/disable.md
[custom operator]: {{rootUrl}}/engine/custom-op.md [custom operator]: {{rootUrl}}/engine/custom-op.md
[custom operators]: {{rootUrl}}/engine/custom-op.md [custom operators]: {{rootUrl}}/engine/custom-op.md
[custom syntax]: {{rootUrl}}/engine/custom-syntax.md

2
doc/src/start/features.md
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@ -25,7 +25,7 @@ more control over what a script can (or cannot) do.
| `no_module` | Disable loading external [modules]. | | `no_module` | Disable loading external [modules]. |
| `no_std` | Build for `no-std`. Notice that additional dependencies will be pulled in to replace `std` features. | | `no_std` | Build for `no-std`. Notice that additional dependencies will be pulled in to replace `std` features. |
| `serde` | Enable serialization/deserialization via [`serde`]. Notice that the [`serde`](https://crates.io/crates/serde) crate will be pulled in together with its dependencies. | | `serde` | Enable serialization/deserialization via [`serde`]. Notice that the [`serde`](https://crates.io/crates/serde) crate will be pulled in together with its dependencies. |
| `internals` | Expose internal data structures (e.g. [`AST`] nodes). Beware that Rhai internals are volatile and may change from version to version. | | `internals` | Expose internal data structures (e.g. [`AST`] nodes) and enable defining [custom syntax]. Beware that Rhai internals are volatile and may change from version to version. |
Example Example

337
src/engine.rs
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@ -17,6 +17,9 @@ use crate::utils::StaticVec;
#[cfg(not(feature = "no_float"))] #[cfg(not(feature = "no_float"))]
use crate::parser::FLOAT; use crate::parser::FLOAT;
#[cfg(feature = "internals")]
use crate::syntax::CustomSyntax;
use crate::stdlib::{ use crate::stdlib::{
any::{type_name, TypeId}, any::{type_name, TypeId},
borrow::Cow, borrow::Cow,
@ -82,8 +85,15 @@ pub const KEYWORD_THIS: &str = "this";
pub const FN_TO_STRING: &str = "to_string"; pub const FN_TO_STRING: &str = "to_string";
pub const FN_GET: &str = "get$"; pub const FN_GET: &str = "get$";
pub const FN_SET: &str = "set$"; pub const FN_SET: &str = "set$";
pub const FN_IDX_GET: &str = "$index$get$"; pub const FN_IDX_GET: &str = "index$get$";
pub const FN_IDX_SET: &str = "$index$set$"; pub const FN_IDX_SET: &str = "index$set$";
#[cfg(feature = "internals")]
pub const MARKER_EXPR: &str = "$expr$";
#[cfg(feature = "internals")]
pub const MARKER_BLOCK: &str = "$block$";
#[cfg(feature = "internals")]
pub const MARKER_IDENT: &str = "$ident$";
/// A type specifying the method of chaining. /// A type specifying the method of chaining.
#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)] #[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
@ -273,6 +283,9 @@ pub struct Engine {
pub(crate) disabled_symbols: Option<HashSet<String>>, pub(crate) disabled_symbols: Option<HashSet<String>>,
/// A hashset containing custom keywords and precedence to recognize. /// A hashset containing custom keywords and precedence to recognize.
pub(crate) custom_keywords: Option<HashMap<String, u8>>, pub(crate) custom_keywords: Option<HashMap<String, u8>>,
/// Custom syntax.
#[cfg(feature = "internals")]
pub(crate) custom_syntax: Option<HashMap<String, CustomSyntax>>,
/// Callback closure for implementing the `print` command. /// Callback closure for implementing the `print` command.
pub(crate) print: Callback<str, ()>, pub(crate) print: Callback<str, ()>,
@ -323,6 +336,9 @@ impl Default for Engine {
disabled_symbols: None, disabled_symbols: None,
custom_keywords: None, custom_keywords: None,
#[cfg(feature = "internals")]
custom_syntax: None,
// default print/debug implementations // default print/debug implementations
print: Box::new(default_print), print: Box::new(default_print),
debug: Box::new(default_print), debug: Box::new(default_print),
@ -555,6 +571,9 @@ impl Engine {
disabled_symbols: None, disabled_symbols: None,
custom_keywords: None, custom_keywords: None,
#[cfg(feature = "internals")]
custom_syntax: None,
print: Box::new(|_| {}), print: Box::new(|_| {}),
debug: Box::new(|_| {}), debug: Box::new(|_| {}),
progress: None, progress: None,
@ -1003,6 +1022,81 @@ impl Engine {
return Ok(result); return Ok(result);
} }
/// Call a dot method.
fn call_method(
&self,
state: &mut State,
lib: &Module,
target: &mut Target,
expr: &Expr,
mut idx_val: Dynamic,
level: usize,
) -> Result<(Dynamic, bool), Box<EvalAltResult>> {
let ((name, native, pos), _, hash, _, def_val) = match expr {
Expr::FnCall(x) => x.as_ref(),
_ => unreachable!(),
};
let is_ref = target.is_ref();
let is_value = target.is_value();
let def_val = def_val.as_ref();
// Get a reference to the mutation target Dynamic
let obj = target.as_mut();
let idx = idx_val.downcast_mut::<StaticVec<Dynamic>>().unwrap();
let mut fn_name = name.as_ref();
// Check if it is a FnPtr call
let (result, updated) = if fn_name == KEYWORD_FN_PTR_CALL && obj.is::<FnPtr>() {
// Redirect function name
fn_name = obj.as_str().unwrap();
// Recalculate hash
let hash = calc_fn_hash(empty(), fn_name, idx.len(), empty());
// Arguments are passed as-is
let mut arg_values = idx.iter_mut().collect::<StaticVec<_>>();
let args = arg_values.as_mut();
// Map it to name(args) in function-call style
self.exec_fn_call(
state, lib, fn_name, *native, hash, args, false, false, def_val, level,
)
} else {
let redirected: Option<ImmutableString>;
let mut hash = *hash;
// Check if it is a map method call in OOP style
if let Some(map) = obj.downcast_ref::<Map>() {
if let Some(val) = map.get(fn_name) {
if let Some(f) = val.downcast_ref::<FnPtr>() {
// Remap the function name
redirected = Some(f.get_fn_name().clone());
fn_name = redirected.as_ref().unwrap();
// Recalculate the hash based on the new function name
hash = calc_fn_hash(empty(), fn_name, idx.len(), empty());
}
}
};
// Attached object pointer in front of the arguments
let mut arg_values = once(obj).chain(idx.iter_mut()).collect::<StaticVec<_>>();
let args = arg_values.as_mut();
self.exec_fn_call(
state, lib, fn_name, *native, hash, args, is_ref, true, def_val, level,
)
}
.map_err(|err| err.new_position(*pos))?;
// Feed the changed temp value back
if updated && !is_ref && !is_value {
let new_val = target.as_mut().clone();
target.set_value(new_val)?;
}
Ok((result, updated))
}
/// Chain-evaluate a dot/index chain. /// Chain-evaluate a dot/index chain.
/// Position in `EvalAltResult` is None and must be set afterwards. /// Position in `EvalAltResult` is None and must be set afterwards.
fn eval_dot_index_chain_helper( fn eval_dot_index_chain_helper(
@ -1022,7 +1116,6 @@ impl Engine {
} }
let is_ref = target.is_ref(); let is_ref = target.is_ref();
let is_value = target.is_value();
let next_chain = match rhs { let next_chain = match rhs {
Expr::Index(_) => ChainType::Index, Expr::Index(_) => ChainType::Index,
@ -1031,7 +1124,7 @@ impl Engine {
}; };
// Pop the last index value // Pop the last index value
let mut idx_val = idx_values.pop(); let idx_val = idx_values.pop();
match chain_type { match chain_type {
#[cfg(not(feature = "no_index"))] #[cfg(not(feature = "no_index"))]
@ -1115,69 +1208,7 @@ impl Engine {
match rhs { match rhs {
// xxx.fn_name(arg_expr_list) // xxx.fn_name(arg_expr_list)
Expr::FnCall(x) if x.1.is_none() => { Expr::FnCall(x) if x.1.is_none() => {
let ((name, native, pos), _, hash, _, def_val) = x.as_ref(); self.call_method(state, lib, target, rhs, idx_val, level)
let def_val = def_val.as_ref();
// Get a reference to the mutation target Dynamic
let (result, updated) = {
let obj = target.as_mut();
let idx = idx_val.downcast_mut::<StaticVec<Dynamic>>().unwrap();
let mut fn_name = name.as_ref();
// Check if it is a FnPtr call
if fn_name == KEYWORD_FN_PTR_CALL && obj.is::<FnPtr>() {
// Redirect function name
fn_name = obj.as_str().unwrap();
// Recalculate hash
let hash = calc_fn_hash(empty(), fn_name, idx.len(), empty());
// Arguments are passed as-is
let mut arg_values = idx.iter_mut().collect::<StaticVec<_>>();
let args = arg_values.as_mut();
// Map it to name(args) in function-call style
self.exec_fn_call(
state, lib, fn_name, *native, hash, args, false, false,
def_val, level,
)
} else {
let redirected: Option<ImmutableString>;
let mut hash = *hash;
// Check if it is a map method call in OOP style
if let Some(map) = obj.downcast_ref::<Map>() {
if let Some(val) = map.get(fn_name) {
if let Some(f) = val.downcast_ref::<FnPtr>() {
// Remap the function name
redirected = Some(f.get_fn_name().clone());
fn_name = redirected.as_ref().unwrap();
// Recalculate the hash based on the new function name
hash =
calc_fn_hash(empty(), fn_name, idx.len(), empty());
}
}
};
// Attached object pointer in front of the arguments
let mut arg_values =
once(obj).chain(idx.iter_mut()).collect::<StaticVec<_>>();
let args = arg_values.as_mut();
self.exec_fn_call(
state, lib, fn_name, *native, hash, args, is_ref, true,
def_val, level,
)
}
.map_err(|err| err.new_position(*pos))?
};
// Feed the changed temp value back
if updated && !is_ref && !is_value {
let new_val = target.as_mut().clone();
target.set_value(new_val)?;
}
Ok((result, updated))
} }
// xxx.module::fn_name(...) - syntax error // xxx.module::fn_name(...) - syntax error
Expr::FnCall(_) => unreachable!(), Expr::FnCall(_) => unreachable!(),
@ -1221,16 +1252,26 @@ impl Engine {
.map(|(v, _)| (v, false)) .map(|(v, _)| (v, false))
.map_err(|err| err.new_position(*pos)) .map_err(|err| err.new_position(*pos))
} }
// {xxx:map}.prop[expr] | {xxx:map}.prop.expr // {xxx:map}.sub_lhs[expr] | {xxx:map}.sub_lhs.expr
Expr::Index(x) | Expr::Dot(x) if target.is::<Map>() => { Expr::Index(x) | Expr::Dot(x) if target.is::<Map>() => {
let (prop, expr, pos) = x.as_ref(); let (sub_lhs, expr, pos) = x.as_ref();
let mut val = if let Expr::Property(p) = prop { let mut val = match sub_lhs {
let ((prop, _, _), _) = p.as_ref(); Expr::Property(p) => {
let index = prop.clone().into(); let ((prop, _, _), _) = p.as_ref();
self.get_indexed_mut(state, lib, target, index, *pos, false, level)? let index = prop.clone().into();
} else { self.get_indexed_mut(state, lib, target, index, *pos, false, level)?
unreachable!(); }
// {xxx:map}.fn_name(arg_expr_list)[expr] | {xxx:map}.fn_name(arg_expr_list).expr
Expr::FnCall(x) if x.1.is_none() => {
let (val, _) =
self.call_method(state, lib, target, sub_lhs, idx_val, level)?;
val.into()
}
// {xxx:map}.module::fn_name(...) - syntax error
Expr::FnCall(_) => unreachable!(),
// Others - syntax error
_ => unreachable!(),
}; };
self.eval_dot_index_chain_helper( self.eval_dot_index_chain_helper(
@ -1239,49 +1280,72 @@ impl Engine {
) )
.map_err(|err| err.new_position(*pos)) .map_err(|err| err.new_position(*pos))
} }
// xxx.prop[expr] | xxx.prop.expr // xxx.sub_lhs[expr] | xxx.sub_lhs.expr
Expr::Index(x) | Expr::Dot(x) => { Expr::Index(x) | Expr::Dot(x) => {
let (prop, expr, pos) = x.as_ref(); let (sub_lhs, expr, pos) = x.as_ref();
let args = &mut [target.as_mut(), &mut Default::default()];
let (mut val, updated) = if let Expr::Property(p) = prop { match sub_lhs {
let ((_, getter, _), _) = p.as_ref(); // xxx.prop[expr] | xxx.prop.expr
let args = &mut args[..1]; Expr::Property(p) => {
self.exec_fn_call( let ((_, getter, setter), _) = p.as_ref();
state, lib, getter, true, 0, args, is_ref, true, None, level, let arg_values = &mut [target.as_mut(), &mut Default::default()];
) let args = &mut arg_values[..1];
.map_err(|err| err.new_position(*pos))? let (mut val, updated) = self
} else { .exec_fn_call(
unreachable!(); state, lib, getter, true, 0, args, is_ref, true, None,
}; level,
let val = &mut val; )
let target = &mut val.into(); .map_err(|err| err.new_position(*pos))?;
let (result, may_be_changed) = self let val = &mut val;
.eval_dot_index_chain_helper( let target = &mut val.into();
state, lib, this_ptr, target, expr, idx_values, next_chain, level,
new_val,
)
.map_err(|err| err.new_position(*pos))?;
// Feed the value back via a setter just in case it has been updated let (result, may_be_changed) = self
if updated || may_be_changed { .eval_dot_index_chain_helper(
if let Expr::Property(p) = prop { state, lib, this_ptr, target, expr, idx_values, next_chain,
let ((_, _, setter), _) = p.as_ref(); level, new_val,
// Re-use args because the first &mut parameter will not be consumed )
args[1] = val; .map_err(|err| err.new_position(*pos))?;
self.exec_fn_call(
state, lib, setter, true, 0, args, is_ref, true, None, level, // Feed the value back via a setter just in case it has been updated
) if updated || may_be_changed {
.or_else(|err| match *err { // Re-use args because the first &mut parameter will not be consumed
// If there is no setter, no need to feed it back because the property is read-only arg_values[1] = val;
EvalAltResult::ErrorDotExpr(_, _) => Ok(Default::default()), self.exec_fn_call(
_ => Err(err.new_position(*pos)), state, lib, setter, true, 0, arg_values, is_ref, true,
})?; None, level,
)
.or_else(
|err| match *err {
// If there is no setter, no need to feed it back because the property is read-only
EvalAltResult::ErrorDotExpr(_, _) => {
Ok(Default::default())
}
_ => Err(err.new_position(*pos)),
},
)?;
}
Ok((result, may_be_changed))
} }
} // xxx.fn_name(arg_expr_list)[expr] | xxx.fn_name(arg_expr_list).expr
Expr::FnCall(x) if x.1.is_none() => {
let (mut val, _) =
self.call_method(state, lib, target, sub_lhs, idx_val, level)?;
let val = &mut val;
let target = &mut val.into();
Ok((result, may_be_changed)) self.eval_dot_index_chain_helper(
state, lib, this_ptr, target, expr, idx_values, next_chain,
level, new_val,
)
.map_err(|err| err.new_position(*pos))
}
// xxx.module::fn_name(...) - syntax error
Expr::FnCall(_) => unreachable!(),
// Others - syntax error
_ => unreachable!(),
}
} }
// Syntax error // Syntax error
_ => Err(Box::new(EvalAltResult::ErrorDotExpr( _ => Err(Box::new(EvalAltResult::ErrorDotExpr(
@ -1316,7 +1380,7 @@ impl Engine {
let idx_values = &mut StaticVec::new(); let idx_values = &mut StaticVec::new();
self.eval_indexed_chain( self.eval_indexed_chain(
scope, mods, state, lib, this_ptr, dot_rhs, idx_values, 0, level, scope, mods, state, lib, this_ptr, dot_rhs, chain_type, idx_values, 0, level,
)?; )?;
match dot_lhs { match dot_lhs {
@ -1380,6 +1444,7 @@ impl Engine {
lib: &Module, lib: &Module,
this_ptr: &mut Option<&mut Dynamic>, this_ptr: &mut Option<&mut Dynamic>,
expr: &Expr, expr: &Expr,
chain_type: ChainType,
idx_values: &mut StaticVec<Dynamic>, idx_values: &mut StaticVec<Dynamic>,
size: usize, size: usize,
level: usize, level: usize,
@ -1406,12 +1471,29 @@ impl Engine {
// Evaluate in left-to-right order // Evaluate in left-to-right order
let lhs_val = match lhs { let lhs_val = match lhs {
Expr::Property(_) => Default::default(), // Store a placeholder in case of a property Expr::Property(_) => Default::default(), // Store a placeholder in case of a property
Expr::FnCall(x) if chain_type == ChainType::Dot && x.1.is_none() => {
let arg_values = x
.3
.iter()
.map(|arg_expr| {
self.eval_expr(scope, mods, state, lib, this_ptr, arg_expr, level)
})
.collect::<Result<StaticVec<Dynamic>, _>>()?;
Dynamic::from(arg_values)
}
Expr::FnCall(_) => unreachable!(),
_ => self.eval_expr(scope, mods, state, lib, this_ptr, lhs, level)?, _ => self.eval_expr(scope, mods, state, lib, this_ptr, lhs, level)?,
}; };
// Push in reverse order // Push in reverse order
let chain_type = match expr {
Expr::Index(_) => ChainType::Index,
Expr::Dot(_) => ChainType::Dot,
_ => unreachable!(),
};
self.eval_indexed_chain( self.eval_indexed_chain(
scope, mods, state, lib, this_ptr, rhs, idx_values, size, level, scope, mods, state, lib, this_ptr, rhs, chain_type, idx_values, size, level,
)?; )?;
idx_values.push(lhs_val); idx_values.push(lhs_val);
@ -1595,6 +1677,26 @@ impl Engine {
} }
} }
/// Evaluate an expression tree.
///
/// ## WARNING - Low Level API
///
/// This function is very low level. It evaluates an expression from an AST.
#[cfg(feature = "internals")]
#[deprecated(note = "this method is volatile and may change")]
pub fn eval_expression_tree(
&self,
scope: &mut Scope,
mods: &mut Imports,
state: &mut State,
lib: &Module,
this_ptr: &mut Option<&mut Dynamic>,
expr: &Expr,
level: usize,
) -> Result<Dynamic, Box<EvalAltResult>> {
self.eval_expr(scope, mods, state, lib, this_ptr, expr, level)
}
/// Evaluate an expression /// Evaluate an expression
fn eval_expr( fn eval_expr(
&self, &self,
@ -2027,6 +2129,13 @@ impl Engine {
Expr::False(_) => Ok(false.into()), Expr::False(_) => Ok(false.into()),
Expr::Unit(_) => Ok(().into()), Expr::Unit(_) => Ok(().into()),
#[cfg(feature = "internals")]
Expr::Custom(x) => {
let func = (x.0).1.as_ref();
let exprs = (x.0).0.as_ref();
func(self, scope, mods, state, lib, this_ptr, exprs, level)
}
_ => unreachable!(), _ => unreachable!(),
}; };

1
src/fn_native.rs
View File

@ -1,3 +1,4 @@
//! Module containing interfaces with native-Rust functions.
use crate::any::Dynamic; use crate::any::Dynamic;
use crate::engine::Engine; use crate::engine::Engine;
use crate::module::Module; use crate::module::Module;

12
src/lib.rs
View File

@ -95,6 +95,8 @@ mod scope;
mod serde; mod serde;
mod settings; mod settings;
mod stdlib; mod stdlib;
#[cfg(feature = "internals")]
mod syntax;
mod token; mod token;
mod r#unsafe; mod r#unsafe;
mod utils; mod utils;
@ -157,13 +159,21 @@ pub use optimize::OptimizationLevel;
// Expose internal data structures. // Expose internal data structures.
#[cfg(feature = "internals")]
#[deprecated(note = "this type is volatile and may change")]
pub use error::LexError;
#[cfg(feature = "internals")] #[cfg(feature = "internals")]
#[deprecated(note = "this type is volatile and may change")] #[deprecated(note = "this type is volatile and may change")]
pub use token::{get_next_token, parse_string_literal, InputStream, Token, TokenizeState}; pub use token::{get_next_token, parse_string_literal, InputStream, Token, TokenizeState};
#[cfg(feature = "internals")] #[cfg(feature = "internals")]
#[deprecated(note = "this type is volatile and may change")] #[deprecated(note = "this type is volatile and may change")]
pub use parser::{Expr, ReturnType, ScriptFnDef, Stmt}; pub use parser::{CustomExpr, Expr, ReturnType, ScriptFnDef, Stmt};
#[cfg(feature = "internals")]
#[deprecated(note = "this type is volatile and may change")]
pub use engine::{Imports, State as EvalState};
#[cfg(feature = "internals")] #[cfg(feature = "internals")]
#[deprecated(note = "this type is volatile and may change")] #[deprecated(note = "this type is volatile and may change")]

12
src/optimize.rs
View File

@ -6,6 +6,9 @@ use crate::parser::{map_dynamic_to_expr, Expr, ReturnType, ScriptFnDef, Stmt, AS
use crate::scope::{Entry as ScopeEntry, EntryType as ScopeEntryType, Scope}; use crate::scope::{Entry as ScopeEntry, EntryType as ScopeEntryType, Scope};
use crate::utils::StaticVec; use crate::utils::StaticVec;
#[cfg(feature = "internals")]
use crate::parser::CustomExpr;
use crate::stdlib::{ use crate::stdlib::{
boxed::Box, boxed::Box,
iter::empty, iter::empty,
@ -598,6 +601,15 @@ fn optimize_expr(expr: Expr, state: &mut State) -> Expr {
state.find_constant(&name).expect("should find constant in scope!").clone().set_position(pos) state.find_constant(&name).expect("should find constant in scope!").clone().set_position(pos)
} }
// Custom syntax
#[cfg(feature = "internals")]
Expr::Custom(x) => Expr::Custom(Box::new((
CustomExpr(
(x.0).0.into_iter().map(|expr| optimize_expr(expr, state)).collect(),
(x.0).1),
x.1
))),
// All other expressions - skip // All other expressions - skip
expr => expr, expr => expr,
} }

116
src/parser.rs
View File

@ -10,6 +10,15 @@ use crate::scope::{EntryType as ScopeEntryType, Scope};
use crate::token::{Position, Token, TokenStream}; use crate::token::{Position, Token, TokenStream};
use crate::utils::{StaticVec, StraightHasherBuilder}; use crate::utils::{StaticVec, StraightHasherBuilder};
#[cfg(feature = "internals")]
use crate::engine::{MARKER_BLOCK, MARKER_EXPR, MARKER_IDENT};
#[cfg(feature = "internals")]
use crate::fn_native::Shared;
#[cfg(feature = "internals")]
use crate::syntax::FnCustomSyntaxEval;
use crate::stdlib::{ use crate::stdlib::{
borrow::Cow, borrow::Cow,
boxed::Box, boxed::Box,
@ -568,6 +577,17 @@ impl Stmt {
} }
} }
#[derive(Clone)]
#[cfg(feature = "internals")]
pub struct CustomExpr(pub StaticVec<Expr>, pub Shared<FnCustomSyntaxEval>);
#[cfg(feature = "internals")]
impl fmt::Debug for CustomExpr {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Debug::fmt(&self.0, f)
}
}
/// An expression. /// An expression.
/// ///
/// Each variant is at most one pointer in size (for speed), /// Each variant is at most one pointer in size (for speed),
@ -632,6 +652,9 @@ pub enum Expr {
False(Position), False(Position),
/// () /// ()
Unit(Position), Unit(Position),
/// Custom syntax
#[cfg(feature = "internals")]
Custom(Box<(CustomExpr, Position)>),
} }
impl Default for Expr { impl Default for Expr {
@ -726,6 +749,9 @@ impl Expr {
Self::True(pos) | Self::False(pos) | Self::Unit(pos) => *pos, Self::True(pos) | Self::False(pos) | Self::Unit(pos) => *pos,
Self::Dot(x) | Self::Index(x) => x.0.position(), Self::Dot(x) | Self::Index(x) => x.0.position(),
#[cfg(feature = "internals")]
Self::Custom(x) => x.1,
} }
} }
@ -758,6 +784,9 @@ impl Expr {
Self::Assignment(x) => x.3 = new_pos, Self::Assignment(x) => x.3 = new_pos,
Self::Dot(x) => x.2 = new_pos, Self::Dot(x) => x.2 = new_pos,
Self::Index(x) => x.2 = new_pos, Self::Index(x) => x.2 = new_pos,
#[cfg(feature = "internals")]
Self::Custom(x) => x.1 = new_pos,
} }
self self
@ -861,6 +890,9 @@ impl Expr {
Token::LeftParen => true, Token::LeftParen => true,
_ => false, _ => false,
}, },
#[cfg(feature = "internals")]
Self::Custom(_) => false,
} }
} }
@ -876,6 +908,14 @@ impl Expr {
_ => self, _ => self,
} }
} }
#[cfg(feature = "internals")]
pub fn get_variable_name(&self) -> Option<&str> {
match self {
Self::Variable(x) => Some((x.0).0.as_str()),
_ => None,
}
}
} }
/// Consume a particular token, checking that it is the expected one. /// Consume a particular token, checking that it is the expected one.
@ -2024,6 +2064,80 @@ fn parse_expr(
settings.pos = input.peek().unwrap().1; settings.pos = input.peek().unwrap().1;
settings.ensure_level_within_max_limit(state.max_expr_depth)?; settings.ensure_level_within_max_limit(state.max_expr_depth)?;
// Check if it is a custom syntax.
#[cfg(feature = "internals")]
if let Some(ref custom) = state.engine.custom_syntax {
let (token, pos) = input.peek().unwrap();
let token_pos = *pos;
match token {
Token::Custom(key) if custom.contains_key(key) => {
let custom = custom.get_key_value(key).unwrap();
let (key, syntax) = custom;
input.next().unwrap();
let mut exprs: StaticVec<Expr> = Default::default();
// Adjust the variables stack
match syntax.scope_delta {
delta if delta > 0 => {
state.stack.push(("".to_string(), ScopeEntryType::Normal))
}
delta if delta < 0 && state.stack.len() <= delta.abs() as usize => {
state.stack.clear()
}
delta if delta < 0 => state
.stack
.truncate(state.stack.len() - delta.abs() as usize),
_ => (),
}
for segment in syntax.segments.iter() {
settings.pos = input.peek().unwrap().1;
let settings = settings.level_up();
match segment.as_str() {
MARKER_IDENT => match input.next().unwrap() {
(Token::Identifier(s), pos) => {
exprs.push(Expr::Variable(Box::new(((s, pos), None, 0, None))));
}
(_, pos) => return Err(PERR::VariableExpected.into_err(pos)),
},
MARKER_EXPR => exprs.push(parse_expr(input, state, lib, settings)?),
MARKER_BLOCK => {
let stmt = parse_block(input, state, lib, settings)?;
let pos = stmt.position();
exprs.push(Expr::Stmt(Box::new((stmt, pos))))
}
s => match input.peek().unwrap() {
(Token::Custom(custom), _) if custom == s => {
input.next().unwrap();
}
(t, _) if t.syntax().as_ref() == s => {
input.next().unwrap();
}
(_, pos) => {
return Err(PERR::MissingToken(
s.to_string(),
format!("for '{}' expression", key),
)
.into_err(*pos))
}
},
}
}
return Ok(Expr::Custom(Box::new((
CustomExpr(exprs, syntax.func.clone()),
token_pos,
))));
}
_ => (),
}
}
// Parse expression normally.
let lhs = parse_unary(input, state, lib, settings.level_up())?; let lhs = parse_unary(input, state, lib, settings.level_up())?;
parse_binary_op(input, state, lib, 1, lhs, settings.level_up()) parse_binary_op(input, state, lib, 1, lhs, settings.level_up())
} }
@ -2297,7 +2411,7 @@ fn parse_import(
fn parse_export( fn parse_export(
input: &mut TokenStream, input: &mut TokenStream,
state: &mut ParseState, state: &mut ParseState,
lib: &mut FunctionsLib, _lib: &mut FunctionsLib,
mut settings: ParseSettings, mut settings: ParseSettings,
) -> Result<Stmt, ParseError> { ) -> Result<Stmt, ParseError> {
settings.pos = eat_token(input, Token::Export); settings.pos = eat_token(input, Token::Export);

151
src/syntax.rs Normal file
View File

@ -0,0 +1,151 @@
//! Module containing implementation for custom syntax.
#![cfg(feature = "internals")]
use crate::any::Dynamic;
use crate::engine::{Engine, Imports, State, MARKER_BLOCK, MARKER_EXPR, MARKER_IDENT};
use crate::error::LexError;
use crate::fn_native::{SendSync, Shared};
use crate::module::Module;
use crate::parser::Expr;
use crate::result::EvalAltResult;
use crate::scope::Scope;
use crate::token::{is_valid_identifier, Token};
use crate::utils::StaticVec;
use crate::stdlib::{
fmt,
rc::Rc,
string::{String, ToString},
sync::Arc,
};
/// A general function trail object.
#[cfg(not(feature = "sync"))]
pub type FnCustomSyntaxEval = dyn Fn(
&Engine,
&mut Scope,
&mut Imports,
&mut State,
&Module,
&mut Option<&mut Dynamic>,
&[Expr],
usize,
) -> Result<Dynamic, Box<EvalAltResult>>;
/// A general function trail object.
#[cfg(feature = "sync")]
pub type FnCustomSyntaxEval = dyn Fn(
&Engine,
&mut Scope,
&mut Imports,
&mut State,
&Module,
&mut Option<&mut Dynamic>,
&[Expr],
usize,
) -> Result<Dynamic, Box<EvalAltResult>>
+ Send
+ Sync;
#[derive(Clone)]
pub struct CustomSyntax {
pub segments: StaticVec<String>,
pub func: Shared<FnCustomSyntaxEval>,
pub scope_delta: isize,
}
impl fmt::Debug for CustomSyntax {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Debug::fmt(&self.segments, f)
}
}
impl Engine {
pub fn register_custom_syntax<S: AsRef<str> + ToString>(
&mut self,
value: &[S],
scope_delta: isize,
func: impl Fn(
&Engine,
&mut Scope,
&mut Imports,
&mut State,
&Module,
&mut Option<&mut Dynamic>,
&[Expr],
usize,
) -> Result<Dynamic, Box<EvalAltResult>>
+ SendSync
+ 'static,
) -> Result<(), Box<LexError>> {
if value.is_empty() {
return Err(Box::new(LexError::ImproperSymbol("".to_string())));
}
let mut segments: StaticVec<_> = Default::default();
for s in value {
let seg = match s.as_ref() {
// Markers not in first position
MARKER_EXPR | MARKER_BLOCK | MARKER_IDENT if !segments.is_empty() => s.to_string(),
// Standard symbols not in first position
s if !segments.is_empty() && Token::lookup_from_syntax(s).is_some() => {
if self
.disabled_symbols
.as_ref()
.map(|d| d.contains(s))
.unwrap_or(false)
{
// If symbol is disabled, make it a custom keyword
if self.custom_keywords.is_none() {
self.custom_keywords = Some(Default::default());
}
if !self.custom_keywords.as_ref().unwrap().contains_key(s) {
self.custom_keywords.as_mut().unwrap().insert(s.into(), 0);
}
}
s.into()
}
// Identifier
s if is_valid_identifier(s.chars()) => {
if self.custom_keywords.is_none() {
self.custom_keywords = Some(Default::default());
}
if !self.custom_keywords.as_ref().unwrap().contains_key(s) {
self.custom_keywords.as_mut().unwrap().insert(s.into(), 0);
}
s.into()
}
// Anything else is an error
_ => return Err(Box::new(LexError::ImproperSymbol(s.to_string()))),
};
segments.push(seg);
}
let key = segments.remove(0);
let syntax = CustomSyntax {
segments,
#[cfg(not(feature = "sync"))]
func: Rc::new(func),
#[cfg(feature = "sync")]
func: Arc::new(func),
scope_delta,
};
if self.custom_syntax.is_none() {
self.custom_syntax = Some(Default::default());
}
self.custom_syntax
.as_mut()
.unwrap()
.insert(key, syntax.into());
Ok(())
}
}

208
src/token.rs
View File

@ -312,6 +312,87 @@ impl Token {
} }
} }
/// Reverse lookup a token from a piece of syntax.
pub fn lookup_from_syntax(syntax: &str) -> Option<Self> {
use Token::*;
Some(match syntax {
"{" => LeftBrace,
"}" => RightBrace,
"(" => LeftParen,
")" => RightParen,
"[" => LeftBracket,
"]" => RightBracket,
"+" => Plus,
"-" => Minus,
"*" => Multiply,
"/" => Divide,
";" => SemiColon,
":" => Colon,
"::" => DoubleColon,
"," => Comma,
"." => Period,
"#{" => MapStart,
"=" => Equals,
"true" => True,
"false" => False,
"let" => Let,
"const" => Const,
"if" => If,
"else" => Else,
"while" => While,
"loop" => Loop,
"for" => For,
"in" => In,
"<" => LessThan,
">" => GreaterThan,
"!" => Bang,
"<=" => LessThanEqualsTo,
">=" => GreaterThanEqualsTo,
"==" => EqualsTo,
"!=" => NotEqualsTo,
"|" => Pipe,
"||" => Or,
"&" => Ampersand,
"&&" => And,
#[cfg(not(feature = "no_function"))]
"fn" => Fn,
"continue" => Continue,
"break" => Break,
"return" => Return,
"throw" => Throw,
"+=" => PlusAssign,
"-=" => MinusAssign,
"*=" => MultiplyAssign,
"/=" => DivideAssign,
"<<=" => LeftShiftAssign,
">>=" => RightShiftAssign,
"&=" => AndAssign,
"|=" => OrAssign,
"^=" => XOrAssign,
"<<" => LeftShift,
">>" => RightShift,
"^" => XOr,
"%" => Modulo,
"%=" => ModuloAssign,
"~" => PowerOf,
"~=" => PowerOfAssign,
#[cfg(not(feature = "no_function"))]
"private" => Private,
#[cfg(not(feature = "no_module"))]
"import" => Import,
#[cfg(not(feature = "no_module"))]
"export" => Export,
#[cfg(not(feature = "no_module"))]
"as" => As,
"===" | "!==" | "->" | "<-" | "=>" | ":=" | "::<" | "(*" | "*)" | "#" => {
Reserved(syntax.into())
}
_ => return None,
})
}
// Is this token EOF? // Is this token EOF?
pub fn is_eof(&self) -> bool { pub fn is_eof(&self) -> bool {
use Token::*; use Token::*;
@ -450,7 +531,7 @@ impl Token {
} }
} }
/// Is this token a keyword? /// Is this token a standard keyword?
pub fn is_keyword(&self) -> bool { pub fn is_keyword(&self) -> bool {
use Token::*; use Token::*;
@ -467,6 +548,22 @@ impl Token {
_ => false, _ => false,
} }
} }
/// Is this token a reserved keyword?
pub fn is_reserved(&self) -> bool {
match self {
Self::Reserved(_) => true,
_ => false,
}
}
/// Is this token a custom keyword?
pub fn is_custom(&self) -> bool {
match self {
Self::Custom(_) => true,
_ => false,
}
}
} }
impl From<Token> for String { impl From<Token> for String {
@ -628,9 +725,9 @@ pub fn parse_string_literal(
} }
/// Consume the next character. /// Consume the next character.
fn eat_next(stream: &mut impl InputStream, pos: &mut Position) { fn eat_next(stream: &mut impl InputStream, pos: &mut Position) -> Option<char> {
stream.get_next();
pos.advance(); pos.advance();
stream.get_next()
} }
/// Scan for a block comment until the end. /// Scan for a block comment until the end.
@ -858,35 +955,8 @@ fn get_next_token_inner(
} }
return Some(( return Some((
match identifier.as_str() { Token::lookup_from_syntax(&identifier)
"true" => Token::True, .unwrap_or_else(|| Token::Identifier(identifier)),
"false" => Token::False,
"let" => Token::Let,
"const" => Token::Const,
"if" => Token::If,
"else" => Token::Else,
"while" => Token::While,
"loop" => Token::Loop,
"continue" => Token::Continue,
"break" => Token::Break,
"return" => Token::Return,
"throw" => Token::Throw,
"for" => Token::For,
"in" => Token::In,
#[cfg(not(feature = "no_function"))]
"private" => Token::Private,
#[cfg(not(feature = "no_module"))]
"import" => Token::Import,
#[cfg(not(feature = "no_module"))]
"export" => Token::Export,
#[cfg(not(feature = "no_module"))]
"as" => Token::As,
#[cfg(not(feature = "no_function"))]
"fn" => Token::Fn,
_ => Token::Identifier(identifier),
},
start_pos, start_pos,
)); ));
} }
@ -933,7 +1003,10 @@ fn get_next_token_inner(
('}', _) => return Some((Token::RightBrace, start_pos)), ('}', _) => return Some((Token::RightBrace, start_pos)),
// Parentheses // Parentheses
('(', '*') => return Some((Token::Reserved("(*".into()), start_pos)), ('(', '*') => {
eat_next(stream, pos);
return Some((Token::Reserved("(*".into()), start_pos));
}
('(', _) => return Some((Token::LeftParen, start_pos)), ('(', _) => return Some((Token::LeftParen, start_pos)),
(')', _) => return Some((Token::RightParen, start_pos)), (')', _) => return Some((Token::RightParen, start_pos)),
@ -947,6 +1020,7 @@ fn get_next_token_inner(
eat_next(stream, pos); eat_next(stream, pos);
return Some((Token::MapStart, start_pos)); return Some((Token::MapStart, start_pos));
} }
('#', _) => return Some((Token::Reserved("#".into()), start_pos)),
// Operators // Operators
('+', '=') => { ('+', '=') => {
@ -962,11 +1036,17 @@ fn get_next_token_inner(
eat_next(stream, pos); eat_next(stream, pos);
return Some((Token::MinusAssign, start_pos)); return Some((Token::MinusAssign, start_pos));
} }
('-', '>') => return Some((Token::Reserved("->".into()), start_pos)), ('-', '>') => {
eat_next(stream, pos);
return Some((Token::Reserved("->".into()), start_pos));
}
('-', _) if !state.non_unary => return Some((Token::UnaryMinus, start_pos)), ('-', _) if !state.non_unary => return Some((Token::UnaryMinus, start_pos)),
('-', _) => return Some((Token::Minus, start_pos)), ('-', _) => return Some((Token::Minus, start_pos)),
('*', ')') => return Some((Token::Reserved("*)".into()), start_pos)), ('*', ')') => {
eat_next(stream, pos);
return Some((Token::Reserved("*)".into()), start_pos));
}
('*', '=') => { ('*', '=') => {
eat_next(stream, pos); eat_next(stream, pos);
return Some((Token::MultiplyAssign, start_pos)); return Some((Token::MultiplyAssign, start_pos));
@ -1031,31 +1111,42 @@ fn get_next_token_inner(
// Warn against `===` // Warn against `===`
if stream.peek_next() == Some('=') { if stream.peek_next() == Some('=') {
eat_next(stream, pos);
return Some((Token::Reserved("===".into()), start_pos)); return Some((Token::Reserved("===".into()), start_pos));
} }
return Some((Token::EqualsTo, start_pos)); return Some((Token::EqualsTo, start_pos));
} }
('=', '>') => return Some((Token::Reserved("=>".into()), start_pos)), ('=', '>') => {
eat_next(stream, pos);
return Some((Token::Reserved("=>".into()), start_pos));
}
('=', _) => return Some((Token::Equals, start_pos)), ('=', _) => return Some((Token::Equals, start_pos)),
(':', ':') => { (':', ':') => {
eat_next(stream, pos); eat_next(stream, pos);
if stream.peek_next() == Some('<') { if stream.peek_next() == Some('<') {
eat_next(stream, pos);
return Some((Token::Reserved("::<".into()), start_pos)); return Some((Token::Reserved("::<".into()), start_pos));
} }
return Some((Token::DoubleColon, start_pos)); return Some((Token::DoubleColon, start_pos));
} }
(':', '=') => return Some((Token::Reserved(":=".into()), start_pos)), (':', '=') => {
eat_next(stream, pos);
return Some((Token::Reserved(":=".into()), start_pos));
}
(':', _) => return Some((Token::Colon, start_pos)), (':', _) => return Some((Token::Colon, start_pos)),
('<', '=') => { ('<', '=') => {
eat_next(stream, pos); eat_next(stream, pos);
return Some((Token::LessThanEqualsTo, start_pos)); return Some((Token::LessThanEqualsTo, start_pos));
} }
('<', '-') => return Some((Token::Reserved("<-".into()), start_pos)), ('<', '-') => {
eat_next(stream, pos);
return Some((Token::Reserved("<-".into()), start_pos));
}
('<', '<') => { ('<', '<') => {
eat_next(stream, pos); eat_next(stream, pos);
@ -1094,6 +1185,7 @@ fn get_next_token_inner(
eat_next(stream, pos); eat_next(stream, pos);
if stream.peek_next() == Some('=') { if stream.peek_next() == Some('=') {
eat_next(stream, pos);
return Some((Token::Reserved("!==".into()), start_pos)); return Some((Token::Reserved("!==".into()), start_pos));
} }
@ -1163,40 +1255,42 @@ fn get_next_token_inner(
} }
/// A type that implements the `InputStream` trait. /// A type that implements the `InputStream` trait.
/// Multiple charaacter streams are jointed together to form one single stream. /// Multiple character streams are jointed together to form one single stream.
pub struct MultiInputsStream<'a> { pub struct MultiInputsStream<'a> {
/// The input character streams. /// The input character streams.
streams: StaticVec<Peekable<Chars<'a>>>, streams: StaticVec<Peekable<Chars<'a>>>,
/// The current stream index.
index: usize,
} }
impl InputStream for MultiInputsStream<'_> { impl InputStream for MultiInputsStream<'_> {
/// Get the next character /// Get the next character
fn get_next(&mut self) -> Option<char> { fn get_next(&mut self) -> Option<char> {
loop { loop {
if self.streams.is_empty() { if self.index >= self.streams.len() {
// No more streams // No more streams
return None; return None;
} else if let Some(ch) = self.streams[0].next() { } else if let Some(ch) = self.streams[self.index].next() {
// Next character in current stream // Next character in current stream
return Some(ch); return Some(ch);
} else { } else {
// Jump to the next stream // Jump to the next stream
let _ = self.streams.remove(0); self.index += 1;
} }
} }
} }
/// Peek the next character /// Peek the next character
fn peek_next(&mut self) -> Option<char> { fn peek_next(&mut self) -> Option<char> {
loop { loop {
if self.streams.is_empty() { if self.index >= self.streams.len() {
// No more streams // No more streams
return None; return None;
} else if let Some(ch) = self.streams[0].peek() { } else if let Some(&ch) = self.streams[self.index].peek() {
// Next character in current stream // Next character in current stream
return Some(*ch); return Some(ch);
} else { } else {
// Jump to the next stream // Jump to the next stream
let _ = self.streams.remove(0); self.index += 1;
} }
} }
} }
@ -1252,7 +1346,11 @@ impl<'a> Iterator for TokenIterator<'a, '_> {
.to_string(), .to_string(),
))), ))),
"(*" | "*)" => Token::LexError(Box::new(LERR::ImproperSymbol( "(*" | "*)" => Token::LexError(Box::new(LERR::ImproperSymbol(
"'(* .. *)' is not a valid comment style. This is not Pascal! Should it be '/* .. */'?" "'(* .. *)' is not a valid comment format. This is not Pascal! Should it be '/* .. */'?"
.to_string(),
))),
"#" => Token::LexError(Box::new(LERR::ImproperSymbol(
"'#' is not a valid symbol. Should it be '#{'?"
.to_string(), .to_string(),
))), ))),
token => Token::LexError(Box::new(LERR::ImproperSymbol( token => Token::LexError(Box::new(LERR::ImproperSymbol(
@ -1260,6 +1358,17 @@ impl<'a> Iterator for TokenIterator<'a, '_> {
))), ))),
}, pos)), }, pos)),
(r @ Some(_), None, None) => r, (r @ Some(_), None, None) => r,
(Some((Token::Identifier(s), pos)), _, Some(custom)) if custom.contains_key(&s) => {
// Convert custom keywords
Some((Token::Custom(s), pos))
}
(Some((token, pos)), _, Some(custom))
if (token.is_keyword() || token.is_operator() || token.is_reserved())
&& custom.contains_key(token.syntax().as_ref()) =>
{
// Convert into custom keywords
Some((Token::Custom(token.syntax().into()), pos))
}
(Some((token, pos)), Some(disabled), _) (Some((token, pos)), Some(disabled), _)
if token.is_operator() && disabled.contains(token.syntax().as_ref()) => if token.is_operator() && disabled.contains(token.syntax().as_ref()) =>
{ {
@ -1275,10 +1384,6 @@ impl<'a> Iterator for TokenIterator<'a, '_> {
// Convert disallowed keywords into identifiers // Convert disallowed keywords into identifiers
Some((Token::Identifier(token.syntax().into()), pos)) Some((Token::Identifier(token.syntax().into()), pos))
} }
(Some((Token::Identifier(s), pos)), _, Some(custom)) if custom.contains_key(&s) => {
// Convert custom keywords
Some((Token::Custom(s), pos))
}
(r, _, _) => r, (r, _, _) => r,
} }
} }
@ -1298,6 +1403,7 @@ pub fn lex<'a, 'e>(input: &'a [&'a str], engine: &'e Engine) -> TokenIterator<'a
pos: Position::new(1, 0), pos: Position::new(1, 0),
stream: MultiInputsStream { stream: MultiInputsStream {
streams: input.iter().map(|s| s.chars().peekable()).collect(), streams: input.iter().map(|s| s.chars().peekable()).collect(),
index: 0,
}, },
} }
} }

29
src/utils.rs
View File

@ -356,10 +356,13 @@ impl<T> StaticVec<T> {
panic!("nothing to pop!"); panic!("nothing to pop!");
} }
let result = if self.is_fixed_storage() { if self.is_fixed_storage() {
self.extract_from_list(self.len - 1) let value = self.extract_from_list(self.len - 1);
self.len -= 1;
value
} else { } else {
let value = self.more.pop().unwrap(); let value = self.more.pop().unwrap();
self.len -= 1;
// Move back to the fixed list // Move back to the fixed list
if self.more.len() == MAX_STATIC_VEC { if self.more.len() == MAX_STATIC_VEC {
@ -370,11 +373,7 @@ impl<T> StaticVec<T> {
} }
value value
}; }
self.len -= 1;
result
} }
/// Remove a value from this `StaticVec` at a particular position. /// Remove a value from this `StaticVec` at a particular position.
/// ///
@ -386,18 +385,20 @@ impl<T> StaticVec<T> {
panic!("index OOB in StaticVec"); panic!("index OOB in StaticVec");
} }
let result = if self.is_fixed_storage() { if self.is_fixed_storage() {
let value = self.extract_from_list(index); let value = self.extract_from_list(index);
// Move all items one slot to the left // Move all items one slot to the left
for x in index..self.len - 1 { for x in index + 1..self.len - 1 {
let orig_value = self.extract_from_list(x + 1); let orig_value = self.extract_from_list(x);
self.set_into_list(x, orig_value, false); self.set_into_list(x - 1, orig_value, false);
} }
self.len -= 1;
value value
} else { } else {
let value = self.more.remove(index); let value = self.more.remove(index);
self.len -= 1;
// Move back to the fixed list // Move back to the fixed list
if self.more.len() == MAX_STATIC_VEC { if self.more.len() == MAX_STATIC_VEC {
@ -408,11 +409,7 @@ impl<T> StaticVec<T> {
} }
value value
}; }
self.len -= 1;
result
} }
/// Get the number of items in this `StaticVec`. /// Get the number of items in this `StaticVec`.
#[inline(always)] #[inline(always)]

104
tests/maps.rs
View File

@ -21,7 +21,7 @@ fn test_map_indexing() -> Result<(), Box<EvalAltResult>> {
r#" r#"
let y = #{d: 1, "e": #{a: 42, b: 88, "": "hello"}, " 123 xyz": 9}; let y = #{d: 1, "e": #{a: 42, b: 88, "": "hello"}, " 123 xyz": 9};
y.e[""][4] y.e[""][4]
"# "#
)?, )?,
'o' 'o'
); );
@ -47,7 +47,7 @@ fn test_map_indexing() -> Result<(), Box<EvalAltResult>> {
let x = #{a: 1, b: 2, c: 3}; let x = #{a: 1, b: 2, c: 3};
let c = x.remove("c"); let c = x.remove("c");
x.len() + c x.len() + c
"# "#
)?, )?,
5 5
); );
@ -58,7 +58,7 @@ fn test_map_indexing() -> Result<(), Box<EvalAltResult>> {
let y = #{b: 42, d: 9}; let y = #{b: 42, d: 9};
x.mixin(y); x.mixin(y);
x.len() + x.b x.len() + x.b
" "
)?, )?,
46 46
); );
@ -68,7 +68,7 @@ fn test_map_indexing() -> Result<(), Box<EvalAltResult>> {
let x = #{a: 1, b: 2, c: 3}; let x = #{a: 1, b: 2, c: 3};
x += #{b: 42, d: 9}; x += #{b: 42, d: 9};
x.len() + x.b x.len() + x.b
" "
)?, )?,
46 46
); );
@ -79,7 +79,7 @@ fn test_map_indexing() -> Result<(), Box<EvalAltResult>> {
let x = #{a: 1, b: 2, c: 3}; let x = #{a: 1, b: 2, c: 3};
let y = #{b: 42, d: 9}; let y = #{b: 42, d: 9};
x + y x + y
" "
)? )?
.len(), .len(),
4 4
@ -94,27 +94,9 @@ fn test_map_assign() -> Result<(), Box<EvalAltResult>> {
let x = engine.eval::<Map>(r#"let x = #{a: 1, b: true, "c$": "hello"}; x"#)?; let x = engine.eval::<Map>(r#"let x = #{a: 1, b: true, "c$": "hello"}; x"#)?;
assert_eq!( assert_eq!(x["a"].clone().cast::<INT>(), 1);
x.get("a") assert_eq!(x["b"].clone().cast::<bool>(), true);
.cloned() assert_eq!(x["c$"].clone().cast::<String>(), "hello");
.expect("should have property a")
.cast::<INT>(),
1
);
assert_eq!(
x.get("b")
.cloned()
.expect("should have property b")
.cast::<bool>(),
true
);
assert_eq!(
x.get("c$")
.cloned()
.expect("should have property c$")
.cast::<String>(),
"hello"
);
Ok(()) Ok(())
} }
@ -125,27 +107,9 @@ fn test_map_return() -> Result<(), Box<EvalAltResult>> {
let x = engine.eval::<Map>(r#"#{a: 1, b: true, "c$": "hello"}"#)?; let x = engine.eval::<Map>(r#"#{a: 1, b: true, "c$": "hello"}"#)?;
assert_eq!( assert_eq!(x["a"].clone().cast::<INT>(), 1);
x.get("a") assert_eq!(x["b"].clone().cast::<bool>(), true);
.cloned() assert_eq!(x["c$"].clone().cast::<String>(), "hello");
.expect("should have property a")
.cast::<INT>(),
1
);
assert_eq!(
x.get("b")
.cloned()
.expect("should have property b")
.cast::<bool>(),
true
);
assert_eq!(
x.get("c$")
.cloned()
.expect("should have property c$")
.cast::<String>(),
"hello"
);
Ok(()) Ok(())
} }
@ -167,7 +131,7 @@ fn test_map_for() -> Result<(), Box<EvalAltResult>> {
} }
s s
"# "#
)? )?
.len(), .len(),
11 11
@ -188,41 +152,11 @@ fn test_map_json() -> Result<(), Box<EvalAltResult>> {
assert!(!map.contains_key("x")); assert!(!map.contains_key("x"));
assert_eq!( assert_eq!(map["a"].clone().cast::<INT>(), 1);
map.get("a") assert_eq!(map["b"].clone().cast::<bool>(), true);
.cloned() assert_eq!(map["c"].clone().cast::<INT>(), 42);
.expect("should have property a") assert_eq!(map["$d e f!"].clone().cast::<String>(), "hello");
.cast::<INT>(), assert_eq!(map["z"].clone().cast::<()>(), ());
1
);
assert_eq!(
map.get("b")
.cloned()
.expect("should have property b")
.cast::<bool>(),
true
);
assert_eq!(
map.get("c")
.cloned()
.expect("should have property a")
.cast::<INT>(),
42
);
assert_eq!(
map.get("$d e f!")
.cloned()
.expect("should have property $d e f!")
.cast::<String>(),
"hello"
);
assert_eq!(
map.get("z")
.cloned()
.expect("should have property z")
.cast::<()>(),
()
);
#[cfg(not(feature = "no_index"))] #[cfg(not(feature = "no_index"))]
{ {
@ -241,7 +175,7 @@ fn test_map_json() -> Result<(), Box<EvalAltResult>> {
} }
s s
"# "#
)? )?
.len(), .len(),
11 11
@ -265,7 +199,7 @@ fn test_map_oop() -> Result<(), Box<EvalAltResult>> {
obj.action(2); obj.action(2);
obj.data obj.data
"#, "#,
)?, )?,
42 42
); );

77
tests/syntax.rs Normal file
View File

@ -0,0 +1,77 @@
#![cfg(feature = "internals")]
use rhai::{
Dynamic, Engine, EvalAltResult, EvalState, Expr, Imports, LexError, Module, Scope, INT,
};
#[test]
fn test_custom_syntax() -> Result<(), Box<EvalAltResult>> {
let mut engine = Engine::new();
// Disable 'while' and make sure it still works with custom syntax
engine.disable_symbol("while");
engine.consume("while false {}").expect_err("should error");
engine.consume("let while = 0")?;
engine
.register_custom_syntax(
&[
"do", "|", "$ident$", "|", "->", "$block$", "while", "$expr$",
],
1,
|engine: &Engine,
scope: &mut Scope,
mods: &mut Imports,
state: &mut EvalState,
lib: &Module,
this_ptr: &mut Option<&mut Dynamic>,
inputs: &[Expr],
level: usize| {
let var_name = inputs[0].get_variable_name().unwrap().to_string();
let stmt = inputs.get(1).unwrap();
let expr = inputs.get(2).unwrap();
scope.push(var_name, 0 as INT);
loop {
engine.eval_expression_tree(scope, mods, state, lib, this_ptr, stmt, level)?;
if !engine
.eval_expression_tree(scope, mods, state, lib, this_ptr, expr, level)?
.as_bool()
.map_err(|_| {
EvalAltResult::ErrorBooleanArgMismatch(
"do-while".into(),
expr.position(),
)
})?
{
break;
}
}
Ok(().into())
},
)
.unwrap();
// 'while' is now a custom keyword so this it can no longer be a variable
engine.consume("let while = 0").expect_err("should error");
assert_eq!(
engine.eval::<INT>(
r"
do |x| -> { x += 1 } while x < 42;
x
"
)?,
42
);
// The first symbol must be an identifier
assert!(matches!(
*engine.register_custom_syntax(&["!"], 0, |_, _, _, _, _, _, _, _| Ok(().into())).expect_err("should error"),
LexError::ImproperSymbol(s) if s == "!"
));
Ok(())
}