Brummel
9c5506b83e
This commit introduces support for unhygienic macro expansion using the `~ident` syntax. When an identifier is prefixed with a tilde (`~`) within a macro template, it is no longer subject to hygienic renaming. Instead, it directly refers to a binding in the call site's environment. This allows macros to interact with variables defined outside the macro's scope, such as: - Modifying call-site variables. - Capturing call-site variables as upvalues in closures. - Defining new variables that are visible in the call site. A new test case `test_macro_tilde_nonparam_assign` has been added to verify this functionality. Previously, unhygienic escapes were implicitly handled by `SyntaxKind::Identifier` if they were not macro parameters. This change makes this behavior explicit and correctly handles non-parameter identifiers by returning a bare symbol.
112 lines
3.7 KiB
Rust
112 lines
3.7 KiB
Rust
use myc::ast::environment::Environment;
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// --- Tests for ~ident (non-parameter unhygienic escape) ---
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#[test]
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fn test_tilde_nonparam_assign_single() {
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// ~x where x is not a parameter reaches the call-site variable.
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let env = Environment::new();
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let res = env
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.run_script("(do (def x 0) (macro inc-x [] `(assign ~x (+ ~x 1))) (inc-x) x)")
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.expect("should increment x");
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assert_eq!(format!("{}", res), "1");
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}
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#[test]
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fn test_tilde_nonparam_assign_multiple_expansions() {
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// Multiple expansions of the same macro do not interfere with each other.
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let env = Environment::new();
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let res = env
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.run_script(
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"(do (def x 0) (macro inc-x [] `(assign ~x (+ ~x 1))) (inc-x) (inc-x) (inc-x) x)",
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)
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.expect("should increment x three times");
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assert_eq!(format!("{}", res), "3");
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}
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#[test]
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fn test_tilde_nonparam_def_creates_visible_binding() {
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// ~y as a def pattern creates a visible binding at the call site.
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let env = Environment::new();
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let res = env
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.run_script("(do (macro def-y [] `(def ~y 42)) (def-y) y)")
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.expect("should create visible y");
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assert_eq!(format!("{}", res), "42");
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}
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#[test]
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fn test_tilde_nonparam_upvalue_capture() {
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// ~x inside a lambda captures the call-site variable as an upvalue.
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let env = Environment::new();
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let res = env
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.run_script("(do (def x 10) (macro make-adder [] `(fn [n] (+ n ~x))) (def add-x (make-adder)) (add-x 5))")
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.expect("should capture x as upvalue");
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assert_eq!(format!("{}", res), "15");
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}
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#[test]
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fn test_tilde_nonparam_plain_def_stays_isolated() {
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// A plain template `(def x ...)` (without ~) remains hygienically isolated
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// even when ~x is used in the same template for references.
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let env = Environment::new();
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let res = env
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.run_script("(do (def x 1) (macro double-x [] `(do (def x (* ~x 2)) ~x)) (double-x))")
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.expect("should return call-site x, not macro-internal x");
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// ~x reads the call-site x=1; the plain `def x` creates an isolated x[ctx]=2.
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assert_eq!(format!("{}", res), "1");
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}
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#[test]
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fn test_tilde_nonparam_missing_variable_is_error() {
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// ~x where x does not exist at the call site produces a compile error.
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let env = Environment::new();
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let res = env.run_script("(do (macro inc-x [] `(assign ~x (+ ~x 1))) (inc-x))");
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assert!(res.is_err(), "should fail: x is not defined at call site");
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}
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#[test]
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fn test_macro_inlining_identity_collision() {
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let source = r#"
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(do
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(macro wrap [f] `(fn [x] (~f x)))
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(def add1 (fn [x] (+ x 1)))
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(def add2 (fn [x] (+ x 2)))
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(def w1 (wrap add1))
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(def w2 (wrap add2))
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(w1 (w2 10)))
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"#;
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// 1. Verify the result is correct
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let env_run = Environment::new();
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let res = env_run.run_script(source).expect("Failed to run script");
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assert_eq!(format!("{}", res), "13");
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// 2. Verify that it was actually folded into a constant by the optimizer
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let env_dump = Environment::new();
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let dump = env_dump.dump_ast(source).expect("Failed to dump AST");
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assert!(
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dump.contains("Constant: 13") || dump.contains("Call"),
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"Macro-wrapped calls should be properly handled. Dump:\n{}",
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dump
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);
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}
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#[test]
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fn test_repro_placeholder_in_template_failure() {
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let env = Environment::new();
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let source = r#"
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(do
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(macro repeat [var limit body]
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`((fn [~var __limit]
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(if (< ~var __limit)
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(do ~body (again (+ ~var 1) __limit))))
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0 ~limit))
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(repeat n 10 42))
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"#;
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let res = env.run_script(source);
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assert!(res.is_ok(), "Expansion failed to strip placeholders: {:?}", res.err());
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}
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