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Refactor auto-currying.

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This commit is contained in:
Stephen Chung 2020-07-29 22:43:50 +08:00
parent a5a3bbd399
commit 1465ba2315
4 changed files with 71 additions and 83 deletions
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18
src/lib.rs
View File

@ -48,23 +48,7 @@
//! }
//! ```
//!
//! ## Optional features
//!
//! | Feature | Description |
//! | ------------- | ----------------------------------------------------------------------------------------------------------------------------------|
//! | `unchecked` | Exclude arithmetic checking (such as overflows and division by zero). Beware that a bad script may panic the entire system! |
//! | `no_function` | Disable script-defined functions if not needed. |
//! | `no_module` | Disable loading external modules if not needed. |
//! | `no_index` | Disable arrays and indexing features if not needed. |
//! | `no_object` | Disable support for custom types and objects. |
//! | `no_float` | Disable floating-point numbers and math if not needed. |
//! | `no_optimize` | Disable the script optimizer. |
//! | `only_i32` | Set the system integer type to `i32` and disable all other integer types. `INT` is set to `i32`. |
//! | `only_i64` | Set the system integer type to `i64` and disable all other integer types. `INT` is set to `i64`. |
//! | `no_std` | Build for `no-std`. Notice that additional dependencies will be pulled in to replace `std` features. |
//! | `sync` | Restrict all values types to those that are `Send + Sync`. Under this feature, `Engine`, `Scope` and `AST` are all `Send + Sync`. |
//! | `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 (beware they may be volatile from version to version). |
//! # Documentation
//!
//! See [The Rhai Book](https://schungx.github.io/rhai) for details on the Rhai script engine and language.

1
src/optimize.rs
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@ -20,7 +20,6 @@ use crate::parser::CustomExpr;
use crate::stdlib::{
boxed::Box,
iter::empty,
mem,
string::{String, ToString},
vec,
vec::Vec,

132
src/parser.rs
View File

@ -25,7 +25,7 @@ use crate::stdlib::{
borrow::Cow,
boxed::Box,
char,
collections::HashMap,
collections::{HashMap, HashSet},
fmt, format,
hash::{Hash, Hasher},
iter::empty,
@ -408,10 +408,9 @@ struct ParseState<'e> {
engine: &'e Engine,
/// Encapsulates a local stack with variable names to simulate an actual runtime scope.
stack: Vec<(String, ScopeEntryType)>,
/// Tracks a list of external variables(variables that are not explicitly
/// declared in the scope during AST evaluation).
/// Tracks a list of external variables (variables that are not explicitly declared in the scope).
#[cfg(not(feature = "no_capture"))]
externals: Vec<String>,
externals: HashSet<(String, Position)>,
/// Encapsulates a local stack with variable names to simulate an actual runtime scope.
modules: Vec<String>,
/// Maximum levels of expression nesting.
@ -431,72 +430,39 @@ impl<'e> ParseState<'e> {
) -> Self {
Self {
engine,
#[cfg(not(feature = "unchecked"))] max_expr_depth,
#[cfg(not(feature = "unchecked"))] max_function_expr_depth,
#[cfg(not(feature = "no_capture"))] externals: Default::default(),
#[cfg(not(feature = "unchecked"))]
max_expr_depth,
#[cfg(not(feature = "unchecked"))]
max_function_expr_depth,
#[cfg(not(feature = "no_capture"))]
externals: Default::default(),
stack: Default::default(),
modules: Default::default(),
}
}
/// Find explicitly declared variable by name in the `ParseState`,
/// searching in reverse order.
/// Find explicitly declared variable by name in the `ParseState`, searching in reverse order.
///
/// If the variable is not present in the scope adds it to the list of
/// external variables
/// If the variable is not present in the scope adds it to the list of external variables
///
/// The return value is the offset to be deducted from `Stack::len`,
/// i.e. the top element of the `ParseState` is offset 1.
/// Return `None` when the variable name is not found in the `stack`.
fn access_var(&mut self, name: &str) -> Option<NonZeroUsize> {
let index = self.stack
fn access_var(&mut self, name: &str, pos: Position) -> Option<NonZeroUsize> {
let index = self
.stack
.iter()
.rev()
.enumerate()
.find(|(_, (n, _))| *n == name)
.and_then(|(i, _)| NonZeroUsize::new(i + 1));
if index.is_some() {
return index
}
#[cfg(not(feature = "no_capture"))]
if self.externals.iter().find(|n| *n == name).is_none() {
self.externals.push(name.to_string());
if index.is_none() {
self.externals.insert((name.to_string(), pos));
}
None
}
/// Creates a curry expression from a list of external variables
#[cfg(not(feature = "no_capture"))]
pub fn make_curry_from_externals(&self, fn_expr: Expr, settings: &ParseSettings) -> Expr {
if self.externals.is_empty() {
return fn_expr
}
let mut args = StaticVec::new();
for var in self.externals.iter() {
args.push(Expr::Variable(Box::new((
(var.clone(), settings.pos),
None,
0,
None,
))));
}
Expr::Dot(Box::new((
fn_expr,
Expr::FnCall(Box::new((
(KEYWORD_FN_PTR_CURRY.into(), false, settings.pos),
None,
calc_fn_hash(empty(), KEYWORD_FN_PTR_CURRY, self.externals.len(), empty()),
args,
None,
))),
settings.pos,
)))
index
}
/// Find a module by name in the `ParseState`, searching in reverse.
@ -1632,7 +1598,7 @@ fn parse_primary(
Token::CharConstant(c) => Expr::CharConstant(Box::new((c, settings.pos))),
Token::StringConstant(s) => Expr::StringConstant(Box::new((s.into(), settings.pos))),
Token::Identifier(s) => {
let index = state.access_var(&s);
let index = state.access_var(&s, settings.pos);
Expr::Variable(Box::new(((s, settings.pos), None, 0, index)))
}
// Function call is allowed to have reserved keyword
@ -1855,9 +1821,9 @@ fn parse_unary(
let (expr, func) = parse_anon_fn(input, &mut new_state, lib, settings)?;
#[cfg(not(feature = "no_capture"))]
for closure in new_state.externals {
state.access_var(&closure);
}
new_state.externals.iter().for_each(|(closure, pos)| {
state.access_var(closure, *pos);
});
// Qualifiers (none) + function name + number of arguments.
let hash = calc_fn_hash(empty(), &func.name, func.params.len(), empty());
@ -3084,6 +3050,46 @@ fn parse_fn(
})
}
/// Creates a curried expression from a list of external variables
#[cfg(not(feature = "no_capture"))]
fn make_curry_from_externals(
fn_expr: Expr,
state: &mut ParseState,
settings: &ParseSettings,
) -> Expr {
if state.externals.is_empty() {
return fn_expr;
}
let mut args: StaticVec<_> = Default::default();
state.externals.iter().for_each(|(var_name, pos)| {
args.push(Expr::Variable(Box::new((
(var_name.clone(), *pos),
None,
0,
None,
))));
});
let hash = calc_fn_hash(
empty(),
KEYWORD_FN_PTR_CURRY,
state.externals.len(),
empty(),
);
let fn_call = Expr::FnCall(Box::new((
(KEYWORD_FN_PTR_CURRY.into(), false, settings.pos),
None,
hash,
args,
None,
)));
Expr::Dot(Box::new((fn_expr, fn_call, settings.pos)))
}
/// Parse an anonymous function definition.
#[cfg(not(feature = "no_function"))]
fn parse_anon_fn(
@ -3151,12 +3157,12 @@ fn parse_anon_fn(
let body = parse_stmt(input, state, lib, settings.level_up())
.map(|stmt| stmt.unwrap_or_else(|| Stmt::Noop(pos)))?;
let mut static_params = StaticVec::<String>::new();
let mut static_params: StaticVec<_> = Default::default();
#[cfg(not(feature = "no_capture"))]
for closure in state.externals.iter() {
state.externals.iter().for_each(|(closure, _)| {
static_params.push(closure.clone());
}
});
for param in params.into_iter() {
static_params.push(param.0);
@ -3184,15 +3190,11 @@ fn parse_anon_fn(
pos: settings.pos,
};
#[cfg(not(feature = "no_capture"))]
let expr = state.make_curry_from_externals(
Expr::FnPointer(Box::new((fn_name, settings.pos))),
&settings,
);
#[cfg(feature = "no_capture")]
let expr = Expr::FnPointer(Box::new((fn_name, settings.pos)));
#[cfg(not(feature = "no_capture"))]
let expr = make_curry_from_externals(expr, state, &settings);
Ok((expr, script))
}

3
src/utils.rs
View File

@ -87,6 +87,9 @@ pub fn calc_fn_spec<'a>(
s.finish()
}
/// [INTERNALS] Alias to [`smallvec::SmallVec<[T; 4]>`](https://crates.io/crates/smallvec),
/// which is a specialized `Vec` backed by a small, fixed-size array when there are <= 4 items stored.
/// Exported under the `internals` feature only.
pub type StaticVec<T> = SmallVec<[T; 4]>;
/// The system immutable string type.