54 lines
1.5 KiB
Markdown
54 lines
1.5 KiB
Markdown
Create a Module from an AST
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==========================
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{{#include ../../links.md}}
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It is easy to convert a pre-compiled [`AST`] into a module: just use `Module::eval_ast_as_new`.
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Don't forget the [`export`] statement, otherwise there will be no variables exposed by the module
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other than non-[`private`] functions (unless that's intentional).
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```rust
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use rhai::{Engine, Module};
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let engine = Engine::new();
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// Compile a script into an 'AST'
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let ast = engine.compile(r#"
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// Functions become module functions
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fn calc(x) {
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x + 1
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}
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fn add_len(x, y) {
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x + y.len
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}
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// Imported modules can become sub-modules
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import "another module" as extra;
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// Variables defined at global level can become module variables
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const x = 123;
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let foo = 41;
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let hello;
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// Variable values become constant module variable values
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foo = calc(foo);
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hello = "hello, " + foo + " worlds!";
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// Finally, export the variables and modules
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export
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x as abc, // aliased variable name
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foo,
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hello,
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extra as foobar; // export sub-module
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"#)?;
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// Convert the 'AST' into a module, using the 'Engine' to evaluate it first
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let module = Module::eval_ast_as_new(Scope::new(), &ast, &engine)?;
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// 'module' now can be loaded into a custom 'Scope' for future use. It contains:
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// - sub-module: 'foobar' (renamed from 'extra')
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// - functions: 'calc', 'add_len'
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// - variables: 'abc' (renamed from 'x'), 'foo', 'hello'
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```
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