src/compiler.rs

@@ -100,9 +100,8 @@ impl Compiler {
             return Ok(None);
         }
 
-        // Now that we've validated it, turn it into IR; first we simplify it, then
-        // we do the conversion.
-        let ir = IR::from(syntax.simplify());
+        // Now that we've validated it, turn it into IR.
+        let ir = IR::from(syntax);
 
         // Finally, send all this to Cranelift for conversion into an object file.
         let mut backend = Backend::object_file(Triple::host())?;

src/ir/ast.rs

@@ -57,7 +57,7 @@ impl Arbitrary for Program {
 
     fn arbitrary_with(args: Self::Parameters) -> Self::Strategy {
         crate::syntax::Program::arbitrary_with(args)
-            .prop_map(|x| Program::from(x.simplify()))
+            .prop_map(Program::from)
             .boxed()
     }
 }

src/ir/eval.rs

@@ -71,7 +71,7 @@ impl Expression {
 #[test]
 fn two_plus_three() {
     let input = crate::syntax::Program::parse(0, "x = 2 + 3; print x;").expect("parse works");
-    let ir = Program::from(input.simplify());
+    let ir = Program::from(input);
     let output = ir.eval().expect("runs successfully");
     assert_eq!("x = 5i64\n", &output);
 }
@@ -80,7 +80,7 @@ fn two_plus_three() {
 fn lotsa_math() {
     let input =
         crate::syntax::Program::parse(0, "x = 2 + 3 * 10 / 5 - 1; print x;").expect("parse works");
-    let ir = Program::from(input.simplify());
+    let ir = Program::from(input);
     let output = ir.eval().expect("runs successfully");
     assert_eq!("x = 7i64\n", &output);
 }

src/ir/from_syntax.rs

@@ -1,82 +1,124 @@
 use internment::ArcIntern;
+use std::sync::atomic::AtomicUsize;
 
 use crate::ir::ast as ir;
-use crate::syntax as syntax;
+use crate::syntax;
+
+use super::ValueOrRef;
 
 impl From<syntax::Program> for ir::Program {
     fn from(mut value: syntax::Program) -> Self {
-        ir::Program {
-            statements: value.statements.drain(..).map(Into::into).collect(),
+        let mut statements = Vec::new();
+
+        for stmt in value.statements.drain(..) {
+            statements.append(&mut stmt.simplify());
         }
+
+        ir::Program { statements }
     }
 }
 
-impl From<Vec<syntax::Statement>> for ir::Program {
-    fn from(mut value: Vec<syntax::Statement>) -> Self {
-        ir::Program {
-            statements: value.drain(..).map(Into::into).collect(),
-        }
-    }
-}
-
-impl From<syntax::Statement> for ir::Statement {
+impl From<syntax::Statement> for ir::Program {
     fn from(value: syntax::Statement) -> Self {
-        match value {
-            syntax::Statement::Binding(loc, name, expr) => {
-                ir::Statement::Binding(loc, ArcIntern::from(name), ir::Expression::from(expr))
-            }
-            syntax::Statement::Print(loc, name) => ir::Statement::Print(loc, ArcIntern::from(name)),
+        ir::Program {
+            statements: value.simplify(),
         }
     }
 }
 
-impl From<syntax::Expression> for ir::Expression {
-    fn from(value: syntax::Expression) -> Self {
-        match value {
-            syntax::Expression::Primitive(loc, name, mut exprs) => ir::Expression::Primitive(
-                loc,
-                ir::Primitive::try_from(name.as_str()).unwrap(),
-                exprs.drain(..).map(Into::into).collect(),
-            ),
+impl syntax::Statement {
+    fn simplify(self) -> Vec<ir::Statement> {
+        let mut new_statements = vec![];
+
+        match self {
+            syntax::Statement::Print(loc, name) => {
+                new_statements.push(ir::Statement::Print(loc, ArcIntern::new(name)))
+            }
+            syntax::Statement::Binding(loc, name, value) => {
+                let (mut prereqs, new_value) = value.simplify(&name);
+                new_statements.append(&mut prereqs);
+                new_statements.push(ir::Statement::Binding(loc, ArcIntern::new(name), new_value))
+            }
+        }
+
+        new_statements
+    }
+}
+
+impl syntax::Expression {
+    fn simplify(self, base_name: &str) -> (Vec<ir::Statement>, ir::Expression) {
+        match self {
+            syntax::Expression::Value(loc, val) => (vec![], ir::Expression::Value(loc, val.into())),
             syntax::Expression::Reference(loc, name) => {
-                ir::Expression::Reference(loc, ArcIntern::from(name))
-            }
-            syntax::Expression::Value(loc, value) => {
-                ir::Expression::Value(loc, ir::Value::from(value))
+                (vec![], ir::Expression::Reference(loc, ArcIntern::new(name)))
             }
+            syntax::Expression::Primitive(_, _, _) => {
+                let (prereqs, val_or_ref) = self.rebind(base_name);
+                (prereqs, val_or_ref.into())
             }
         }
     }
 
-impl From<syntax::Expression> for ir::ValueOrRef {
-    fn from(value: syntax::Expression) -> Self {
-        match value {
-            syntax::Expression::Primitive(loc, _, _) => {
-                panic!("{:?}: couldn't convert to valueorref", loc)
+    fn rebind(self, base_name: &str) -> (Vec<ir::Statement>, ir::ValueOrRef) {
+        match self {
+            syntax::Expression::Value(loc, val) => (vec![], ValueOrRef::Value(loc, val.into())),
+            syntax::Expression::Reference(loc, name) => {
+                (vec![], ValueOrRef::Ref(loc, ArcIntern::new(name)))
+            }
+            syntax::Expression::Primitive(loc, prim, mut expressions) => {
+                let new_name = gensym(base_name);
+                let mut prereqs = Vec::new();
+                let mut new_exprs = Vec::new();
+
+                for expr in expressions.drain(..) {
+                    let (mut cur_prereqs, arg) = expr.rebind(base_name);
+                    prereqs.append(&mut cur_prereqs);
+                    new_exprs.push(arg);
                 }
 
-            syntax::Expression::Reference(loc, var) => {
-                ir::ValueOrRef::Ref(loc, ArcIntern::new(var))
-            }
+                let prim = ir::Primitive::try_from(prim.as_str()).unwrap();
+                prereqs.push(ir::Statement::Binding(
+                    loc.clone(),
+                    new_name.clone(),
+                    ir::Expression::Primitive(loc.clone(), prim, new_exprs),
+                ));
 
-            syntax::Expression::Value(loc, val) => ir::ValueOrRef::Value(loc, val.into()),
+                (prereqs, ValueOrRef::Ref(loc, new_name))
+            }
         }
     }
 }
 
 impl From<syntax::Value> for ir::Value {
-    fn from(x: syntax::Value) -> Self {
-        match x {
-            syntax::Value::Number(base, value) => ir::Value::Number(base, value),
+    fn from(value: syntax::Value) -> Self {
+        match value {
+            syntax::Value::Number(base, val) => ir::Value::Number(base, val),
         }
     }
 }
 
+impl From<String> for ir::Primitive {
+    fn from(value: String) -> Self {
+        value.try_into().unwrap()
+    }
+}
+
+fn gensym(name: &str) -> ArcIntern<String> {
+    static COUNTER: AtomicUsize = AtomicUsize::new(0);
+
+    let new_name = format!(
+        "<{}:{}>",
+        name,
+        COUNTER.fetch_add(1, std::sync::atomic::Ordering::SeqCst)
+    );
+    ArcIntern::new(new_name)
+}
+
 proptest::proptest! {
     #[test]
     fn translation_maintains_semantics(input: syntax::Program) {
         let syntax_result = input.eval();
-        let ir = ir::Program::from(input.simplify());
+        let ir = ir::Program::from(input);
         let ir_result = ir.eval();
         assert_eq!(syntax_result, ir_result);
     }

src/repl.rs

@@ -24,7 +24,6 @@ pub struct REPL {
     file_database: SimpleFiles<String, String>,
     jitter: Backend<JITModule>,
     variable_binding_sites: HashMap<String, Location>,
-    gensym_index: usize,
     console: StandardStream,
     console_config: Config,
 }
@@ -72,7 +71,6 @@ impl REPL {
             file_database: SimpleFiles::new(),
             jitter: Backend::jit(None)?,
             variable_binding_sites: HashMap::new(),
-            gensym_index: 1,
             console,
             console_config,
         })
@@ -156,7 +154,7 @@ impl REPL {
             return Ok(());
         }
 
-        let ir = IR::from(syntax.simplify(&mut self.gensym_index));
+        let ir = IR::from(syntax);
         let name = format!("line{}", line_no);
         let function_id = self.jitter.compile_function(&name, ir)?;
         self.jitter.module.finalize_definitions()?;

src/syntax.rs

@@ -34,7 +34,6 @@ mod arbitrary;
 mod ast;
 mod eval;
 mod location;
-pub mod simplify;
 mod tokens;
 lalrpop_mod!(
     #[allow(clippy::just_underscores_and_digits, clippy::clone_on_copy)]

src/syntax/simplify.rs

@@ -1,63 +0,0 @@
-use crate::syntax::ast::{Expression, Program, Statement};
-
-impl Program {
-    pub fn simplify(mut self) -> Self {
-        let mut new_statements = Vec::new();
-        let mut gensym_index = 1;
-
-        for stmt in self.statements.drain(..) {
-            new_statements.append(&mut stmt.simplify(&mut gensym_index));
-        }
-
-        self.statements = new_statements;
-        self
-    }
-}
-
-impl Statement {
-    pub fn simplify(self, gensym_index: &mut usize) -> Vec<Statement> {
-        let mut new_statements = vec![];
-
-        match self {
-            Statement::Print(_, _) => new_statements.push(self),
-            Statement::Binding(_, _, Expression::Reference(_, _)) => new_statements.push(self),
-            Statement::Binding(_, _, Expression::Value(_, _)) => new_statements.push(self),
-            Statement::Binding(loc, name, value) => {
-                let (mut prereqs, new_value) = value.rebind(&name, gensym_index);
-                new_statements.append(&mut prereqs);
-                new_statements.push(Statement::Binding(loc, name, new_value))
-            }
-        }
-
-        new_statements
-    }
-}
-
-impl Expression {
-    fn rebind(self, base_name: &str, gensym_index: &mut usize) -> (Vec<Statement>, Expression) {
-        match self {
-            Expression::Value(_, _) => (vec![], self),
-            Expression::Reference(_, _) => (vec![], self),
-            Expression::Primitive(loc, prim, mut expressions) => {
-                let mut prereqs = Vec::new();
-                let mut new_exprs = Vec::new();
-
-                for expr in expressions.drain(..) {
-                    let (mut cur_prereqs, arg) = expr.rebind(base_name, gensym_index);
-                    prereqs.append(&mut cur_prereqs);
-                    new_exprs.push(arg);
-                }
-
-                let new_name = format!("<{}:{}>", base_name, *gensym_index);
-                *gensym_index += 1;
-                prereqs.push(Statement::Binding(
-                    loc.clone(),
-                    new_name.clone(),
-                    Expression::Primitive(loc.clone(), prim, new_exprs),
-                ));
-
-                (prereqs, Expression::Reference(loc, new_name))
-            }
-        }
-    }
-}