finished var and func numbering

demo.hal

@@ -0,0 +1,3 @@
+bar :: (a: integer) {
+	local := a;
+}

demo.lang

@@ -1,2 +0,0 @@
-a : i32 = 10;
-b := 20 + a;

src/frontend.rs

@@ -1,6 +1,10 @@
 use std::path::Path;
 
-use crate::{err::*, semantic::typecheck, Parser, Statement, Tokenizer};
+use crate::{
+  err::*,
+  semantic::{self},
+  Parser, Statement, Tokenizer,
+};
 
 #[derive(Debug, Clone)]
 pub struct Module {
@@ -26,7 +30,7 @@ impl Module {
   pub fn from_string(file_name: String, source: String) -> Self {
     let tokens = Tokenizer::new(source.chars()).filter(|t| t.0.is_meaningful());
     let statements = Parser::new(tokens);
-    let program = typecheck(statements.collect());
+    let program = semantic::Analyzer::typecheck(statements.collect());
     let mut errors = vec![];
     Self {
       file_name,

src/ir.rs

@@ -1,17 +1,57 @@
-use crate::{semantic::Type, BinaryOp, Immediate, UnaryOp};
+use crate::{
+  BinaryOp, Expression, ExpressionKind, Immediate, UnaryOp,
+  semantic::{Type, VarKind, uid},
+};
 
 #[derive(Debug, Clone)]
 pub enum IR {
   BinOp { op: BinaryOp, type_: Type },
   UnOp { op: UnaryOp, type_: Type },
   Imm(Immediate),
-  NewLocal { uid: usize, type_: Type },
-  AssignLocal { uid: usize },
-  AccessLocal { uid: usize },
-  NewGlobal { uid: usize, type_: Type },
-  AssignGlobal { uid: usize },
-  AccessGlobal { uid: usize },
-  StartFunc { uid: usize },
-  NewParam { uid: usize, type_: Type },
+  NewLocal { uid: uid, type_: Type },
+  AssignLocal { uid: uid },
+  GetLocal { uid: uid },
+  NewGlobal { uid: uid, type_: Type },
+  AssignGlobal { uid: uid },
+  GetGlobal { uid: uid },
+  StartFunc { uid: uid },
+  NewParam { uid: uid, type_: Type },
   EndFunc,
 }
+
+pub struct Compiler {
+  ir: Vec<IR>,
+}
+
+impl Compiler {
+  fn expression(&mut self, expression: Expression) {
+    use ExpressionKind::*;
+    match expression.kind {
+      Immediate(immediate) => {
+        self.ir.push(IR::Imm(immediate));
+      },
+      Identifier(name, var_kind) => match var_kind {
+        VarKind::Global(uid) => self.ir.push(IR::GetGlobal { uid }),
+        VarKind::Local(uid) | VarKind::Param(uid) => {
+          self.ir.push(IR::GetLocal { uid })
+        },
+        VarKind::Function(_) => todo!(),
+        VarKind::Undefined => todo!(),
+      },
+      Binary { op, left, right } => todo!(),
+      Unary { op, child } => todo!(),
+      Parenthesis(expression) => todo!(),
+      FunctionDef {
+        params,
+        returns_str,
+        returns_actual,
+        body,
+        id,
+      } => todo!(),
+      FunctionCall { callee, args } => todo!(),
+      StructDef(vec) => todo!(),
+      StructLiteral { name, args } => todo!(),
+      Field { namespace, field } => todo!(),
+    }
+  }
+}

src/main.rs

@@ -62,10 +62,36 @@ fn test_expression(expr: &str) {
   println!("{:?}", parser.expression(0).unwrap());
 }
 
+fn prints(st: &Statement) {
+  use StatementKind as s;
+  println!("{st:?}");
+  match &st.kind {
+    s::Declaration {
+      value:
+        Expression {
+          kind: ExpressionKind::FunctionDef { body: block, .. },
+          ..
+        },
+      ..
+    }
+    | s::If { block, .. }
+    | s::While { block, .. }
+    | s::Block(block) => {
+      for s in block {
+        prints(s);
+      }
+    },
+    _ => {},
+  };
+}
+
 fn main() -> Result<()> {
-  let module = frontend::Module::from_file("./demo.lang")?;
+  test_expression("asdf.asdf()");
+  /*
+  let module = frontend::Module::from_file("./demo.hal")?;
   for s in &module.program {
-    println!("{s:?}");
+    prints(s);
   }
+  */
   Ok(())
 }

src/parse/expression.rs

@@ -26,7 +26,7 @@ pub enum Immediate {
 #[derive(Clone)]
 pub enum ExpressionKind {
   Immediate(Immediate),
-  Identifier(String),
+  Identifier(String, VarKind),
   Binary {
     op: BinaryOp,
     left: Box<Expression>,
@@ -37,21 +37,22 @@ pub enum ExpressionKind {
     child: Box<Expression>,
   },
   Parenthesis(Box<Expression>),
-  Function {
+  FunctionDef {
     params: Vec<Parameter>,
     returns_str: Option<String>,
     returns_actual: Type,
     body: Vec<Statement>,
+    id: uid,
   },
-  Struct(Vec<Parameter>),
+  FunctionCall {
+    callee: Box<Expression>,
+    args: Vec<Expression>,
+  },
+  StructDef(Vec<Parameter>),
   StructLiteral {
     name: String,
     args: Vec<(String, Expression)>,
   },
-  Call {
-    callee: Box<Expression>,
-    args: Vec<Expression>,
-  },
   Field {
     namespace: Box<Expression>,
     field: Box<Expression>,
@@ -97,19 +98,21 @@ impl std::fmt::Debug for ExpressionKind {
       e::Unary { op: token, child } => {
         write!(f, "({token:?} {child:?})")
       },
-      e::Identifier(i) => write!(f, "{i}"),
-      e::Call { callee, args } => write!(f, "({callee:?} call {args:?})"),
+      e::Identifier(i, _) => write!(f, "{i}"),
+      e::FunctionCall { callee, args } => {
+        write!(f, "({callee:?} call {args:?})")
+      },
       e::Field { namespace, field } => {
         write!(f, "({namespace:?} . {field:?})")
       },
-      e::Function {
+      e::FunctionDef {
         params,
         returns_actual,
         ..
       } => {
         write!(f, "(fn({params:?}) -> {returns_actual:?})")
       },
-      e::Struct(params) => write!(f, "struct {{ {params:?} }}"),
+      e::StructDef(params) => write!(f, "struct {{ {params:?} }}"),
       e::StructLiteral { name, args } => write!(f, "{name} {{ {args:?} }}"),
     }
   }
@@ -217,7 +220,7 @@ impl<I: Iterator<Item = Token>> Parser<I> {
         }
         let Token(_, span2) = self.eat(t::RightParen).span(&span)?;
         current = Expression::new(
-          e::Call {
+          e::FunctionCall {
             callee: current.into(),
             args,
           },
@@ -326,11 +329,12 @@ impl<I: Iterator<Item = Token>> Parser<I> {
           .block()
           .trace_span(span, "while parsing function body")?;
         span = span + span2;
-        e::Function {
+        e::FunctionDef {
           params,
           returns_str,
           returns_actual: Type::Ambiguous,
           body,
+          id: 0,
         }
       },
       // Struct definition
@@ -361,7 +365,7 @@ impl<I: Iterator<Item = Token>> Parser<I> {
           }
         }
         self.eat(t::RightBrace)?;
-        e::Struct(params)
+        e::StructDef(params)
       },
       // Struct literal
       t::Identifier(name) if self.look(1, t::LeftBrace).is_ok() => {
@@ -390,7 +394,7 @@ impl<I: Iterator<Item = Token>> Parser<I> {
       },
       t::Identifier(i) => {
         self.skip(1);
-        e::Identifier(i)
+        e::Identifier(i, VarKind::Undefined)
       },
       // Parenthetical
       t::LeftParen => {

src/parse/statement.rs

@@ -1,4 +1,4 @@
-use crate::semantic::Type;
+use crate::semantic::{Type, VarKind};
 
 use super::*;
 
@@ -10,10 +10,12 @@ pub enum StatementKind {
     type_actual: Type,
     value: Expression,
     mutable: bool,
+    varkind: VarKind,
   },
   Assignment {
     name: String,
     value: Expression,
+    varkind: VarKind,
   },
   If {
     predicate: Expression,
@@ -68,13 +70,14 @@ impl<I: Iterator<Item = Token>> Parser<I> {
           .expression(0)
           .trace_span(span, "while parsing declaration")?;
         span = span + value.span;
-        let no_semicolon = if let ExpressionKind::Function { .. } = value.kind {
-          true
-        } else if let ExpressionKind::Struct(_) = value.kind {
-          true
-        } else {
-          false
-        };
+        let no_semicolon =
+          if let ExpressionKind::FunctionDef { .. } = value.kind {
+            true
+          } else if let ExpressionKind::StructDef(_) = value.kind {
+            true
+          } else {
+            false
+          };
         let s = Statement {
           kind: s::Declaration {
             name,
@@ -82,6 +85,7 @@ impl<I: Iterator<Item = Token>> Parser<I> {
             type_actual: Type::Ambiguous,
             value,
             mutable,
+            varkind: VarKind::Undefined,
           },
           span,
         };
@@ -99,7 +103,11 @@ impl<I: Iterator<Item = Token>> Parser<I> {
           .trace_span(span, "while parsing assignment")?;
         Statement {
           span,
-          kind: s::Assignment { name, value },
+          kind: s::Assignment {
+            name,
+            value,
+            varkind: VarKind::Undefined,
+          },
         }
       },
       // If

src/semantic/analyzer.rs

@@ -0,0 +1,356 @@
+use crate::{
+  BinaryOp, Expression, ExpressionKind, Immediate, Parameter, Statement,
+  StatementKind, UnaryOp,
+  semantic::{Symbol, SymbolTable, Type, VarKind},
+};
+
+use super::primitives::*;
+use crate::err::*;
+
+pub struct Analyzer {
+  table: SymbolTable,
+}
+
+impl Analyzer {
+  pub fn typecheck(statements: Vec<Statement>) -> Vec<Statement> {
+    let mut this = Self {
+      table: SymbolTable::new(),
+    };
+    this.block(statements)
+  }
+
+  fn block(&mut self, block: Vec<Statement>) -> Vec<Statement> {
+    let mut new_block = vec![];
+    for st in block {
+      let span = st.span;
+      let st = match self.statement(st.into()) {
+        Ok(st) => *st,
+        Err(e) => Statement {
+          kind: StatementKind::Error(e),
+          span,
+        },
+      };
+      new_block.push(st);
+    }
+    new_block
+  }
+
+  fn statement(&mut self, mut stmt: Box<Statement>) -> Result<Box<Statement>> {
+    use Primitive as p;
+    use StatementKind as s;
+    match stmt.kind {
+      // Variable declaration
+      s::Declaration {
+        name,
+        type_str,
+        value,
+        mutable,
+        ..
+      } => {
+        let type_lhs = if let Some(ref s) = type_str {
+          self.table.get_type(s).span(&stmt.span)?
+        } else {
+          Type::Ambiguous
+        };
+        let mut value = self.expression(value.into())?;
+        let type_actual = Type::coerce(&type_lhs, &value.type_)
+          .reason(format!(
+            "Expected type '{:?}', found type '{:?}'",
+            type_lhs, value.type_
+          ))
+          .span(&stmt.span)?;
+        value.type_ = type_actual.clone();
+        let varkind = self
+          .table
+          .define_symbol(name.clone(), type_actual.clone(), mutable)
+          .span(&stmt.span)?;
+        stmt.kind = s::Declaration {
+          name,
+          type_str,
+          type_actual,
+          value: *value,
+          mutable,
+          varkind,
+        };
+      },
+      // Variable assignment
+      s::Assignment { name, value, .. } => {
+        let symbol = self.table.find_symbol(&name).span(&stmt.span)?;
+        // Check that it is mutable
+        if !symbol.mutable {
+          return error()
+            .reason(format!("Cannot assign to immutable '{}'", name))
+            .span(&stmt.span);
+        }
+        let mut value = *self.expression(value.into())?;
+        let type_actual =
+          Type::coerce(&symbol.type_, &value.type_).span(&stmt.span)?;
+        value.type_ = type_actual;
+        stmt.kind = s::Assignment {
+          name,
+          value,
+          varkind: symbol.kind,
+        };
+      },
+      s::If {
+        predicate,
+        block,
+        else_,
+      } => {
+        self.table.start_block();
+        let predicate = *self.expression(predicate.into())?;
+        Type::coerce(&Type::Prim(p::boolean), &predicate.type_)
+          .span(&predicate.span)?;
+        let block = self.block(block);
+        let else_ = if let Some(else_) = else_ {
+          Some(self.statement(else_)?)
+        } else {
+          None
+        };
+        stmt.kind = s::If {
+          predicate,
+          block,
+          else_,
+        };
+        self.table.end_block();
+      },
+      s::While { predicate, block } => {
+        self.table.start_block();
+        let predicate = *self.expression(predicate.into())?;
+        Type::coerce(&Type::Prim(p::boolean), &predicate.type_)
+          .span(&predicate.span)?;
+        let block = self.block(block);
+        stmt.kind = s::While { predicate, block };
+        self.table.end_block();
+      },
+      s::Print(e) => {
+        stmt.kind = s::Print(*self.expression(e.into())?);
+      },
+      s::Expression(e) => {
+        stmt.kind = s::Expression(*self.expression(e.into())?);
+      },
+      s::Block(block) => {
+        self.table.start_block();
+        let block = self.block(block);
+        stmt.kind = s::Block(block);
+        self.table.end_block();
+      },
+      s::Error(e) => return Err(e),
+    }
+    Ok(stmt)
+  }
+
+  fn expression(
+    &mut self,
+    mut expr: Box<Expression>,
+  ) -> Result<Box<Expression>> {
+    use ExpressionKind as e;
+    use Immediate as i;
+    use Primitive as p;
+    let type_ = match expr.kind {
+      e::Immediate(ref i) => Type::Prim(match i {
+        i::Integer(_) => p::integer_ambiguous,
+        i::Real(_) => p::real_ambiguous,
+        i::String(_) => p::string,
+        i::Boolean(_) => p::boolean,
+      }),
+      e::Identifier(ref i, ref mut kind) => {
+        let symbol = self.table.find_symbol(i)?;
+        *kind = symbol.kind;
+        self.table.find_symbol(i)?.type_
+      },
+      e::Binary { op, left, right } => {
+        let left = self.expression(left)?;
+        let right = self.expression(right)?;
+        let type_ = Type::binary_op(&left.type_, op, &right.type_)?;
+        expr.kind = e::Binary { left, right, op };
+        type_
+      },
+      e::Unary { op, child } => {
+        let child = self.expression(child)?;
+        let type_ = Type::unary_op(op, &child.type_)?;
+        expr.kind = e::Unary { child, op };
+        type_
+      },
+      e::Parenthesis(inner) => {
+        let inner = self.expression(inner)?;
+        let type_ = inner.type_.clone();
+        expr.kind = e::Parenthesis(inner);
+        type_
+      },
+      e::FunctionDef {
+        mut params,
+        returns_str,
+        mut returns_actual,
+        body,
+        id,
+      } => {
+        self.table.start_func();
+        for p in &mut params {
+          p.type_actual = self.table.get_type(&p.type_str).span(&expr.span)?;
+          self
+            .table
+            .define_param(p.name.clone(), p.type_actual.clone())?;
+        }
+        returns_actual = match &returns_str {
+          Some(s) => self.table.get_type(s).span(&expr.span)?,
+          None => Type::Nothing,
+        };
+        let body = self.block(body);
+        self.table.end_func();
+        expr.kind = e::FunctionDef {
+          params: params.clone(),
+          returns_str,
+          returns_actual: returns_actual.clone(),
+          body,
+          id,
+        };
+        Type::Function {
+          params: params.into_iter().map(|p| p.type_actual).collect(),
+          returns: returns_actual.into(),
+        }
+      },
+      e::FunctionCall { callee, mut args } => {
+        let callee = self.expression(callee)?;
+        // Check that this is actually a function
+        let Type::Function {
+          ref params,
+          ref returns,
+        } = callee.type_
+        else {
+          return error()
+            .reason(format!("Cannot call type {:?}", callee.type_))
+            .span(&callee.span);
+        };
+        // Check for correct number of args
+        if params.len() != args.len() {
+          return error()
+            .reason(format!(
+              "Wrong number of arguments, function expects {}, found {}",
+              params.len(),
+              args.len()
+            ))
+            .span(&callee.span);
+        }
+        // Check for correct arg types
+        for (expect, actual) in params.iter().zip(args.iter_mut()) {
+          *actual = *self.expression(actual.clone().into())?;
+          let coerced_type = Type::coerce(expect, &actual.type_);
+          if let Ok(t) = coerced_type {
+            actual.type_ = t;
+          } else {
+            return error()
+              .reason(format!(
+                "Expected type {expect:?}, found {:?}",
+                actual.type_
+              ))
+              .span(&actual.span);
+          }
+        }
+        let returns = *returns.clone();
+        expr.kind = e::FunctionCall { callee, args };
+        returns
+      },
+      e::StructDef(mut params) => {
+        for p in &mut params {
+          p.type_actual = self.table.get_type(&p.type_str).span(&expr.span)?;
+        }
+        expr.kind = e::StructDef(params.clone());
+        Type::StructDef(params)
+      },
+      e::StructLiteral { name, args } => {
+        let type_ = self.table.get_type(&name).span(&expr.span)?;
+        let Type::Struct(params) = type_ else {
+          return error().reason(format!(
+            "Cannot construct type {:?} as struct literal",
+            type_
+          ));
+        };
+        if args.len() != params.len() {
+          return error().reason(format!(
+            "Incorrect number of parameters for struct '{}'; expected {}, \
+             found {}",
+            name,
+            params.len(),
+            args.len()
+          ));
+        }
+        // TODO out of order params
+        let mut new_args = vec![];
+        for (
+          (argname, argexpr),
+          Parameter {
+            name: pname,
+            type_actual: ptype,
+            ..
+          },
+        ) in args.iter().zip(params.iter())
+        {
+          if argname != pname {
+            return error()
+              .reason(format!(
+                "In struct literal, expected parameter '{pname}', found \
+                 '{argname}'"
+              ))
+              .span(&argexpr.span);
+          }
+          let argspan = argexpr.span;
+          let mut arg = *self
+            .expression(argexpr.clone().into())
+            .trace_span(expr.span, "while parsing struct literal")?;
+          let coerced_type = Type::coerce(ptype, &arg.type_);
+          if let Ok(t) = coerced_type {
+            arg.type_ = t;
+          } else {
+            return error()
+              .reason(format!(
+                "In struct literal, expected type '{ptype:?}', found '{:?}",
+                arg.type_,
+              ))
+              .span(&argspan);
+          }
+          new_args.push((argname.clone(), arg));
+        }
+        expr.kind = e::StructLiteral {
+          name,
+          args: new_args,
+        };
+        Type::Struct(params)
+      },
+      e::Field { namespace, field } => {
+        let namespace = self.expression(namespace)?;
+        // Check that namespace is struct
+        // TODO: fields in other types
+        let Type::Struct(ref params) = namespace.type_ else {
+          return error()
+            .reason(format!("Type {:?} does not have fields", namespace.type_))
+            .span(&namespace.span);
+        };
+        // Check that field is identifier
+        // TODO: tuple fields?
+        let e::Identifier(ref name, _) = field.kind else {
+          return error()
+            .reason("Field must be an identifier")
+            .span(&field.span);
+        };
+        let mut type_ = None;
+        for p in params {
+          if &p.name == name {
+            type_ = Some(p.type_actual.clone());
+            break;
+          }
+        }
+        let type_ = type_
+          .reason(format!(
+            "Type {:?} does not contain field {}",
+            namespace, name
+          ))
+          .span(&field.span)?;
+        expr.kind = e::Field { namespace, field };
+        type_
+      },
+    };
+    expr.type_ = type_;
+    Ok(expr)
+  }
+}

src/semantic/mod.rs

@@ -1,39 +1,138 @@
+mod analyzer;
 mod primitives;
 mod types;
 
-use crate::err::*;
+use crate::{Parameter, err::*};
+pub use analyzer::*;
 pub use primitives::*;
 pub use types::*;
+#[allow(non_camel_case_types)]
+pub type uid = u32;
+
+// Variable and function numbering
+#[derive(Clone, Copy, Debug)]
+pub enum VarKind {
+  Global(uid),
+  Local(uid),
+  Param(uid),
+  Function(uid),
+  Undefined,
+}
+
+impl VarKind {
+  pub fn unwrap(self) -> uid {
+    match self {
+      VarKind::Global(i)
+      | VarKind::Local(i)
+      | VarKind::Param(i)
+      | VarKind::Function(i) => i,
+      VarKind::Undefined => unreachable!("Failed unwrapping uid"),
+    }
+  }
+}
+
+#[derive(Clone, Debug)]
+pub struct Symbol {
+  pub name: String,
+  pub type_: Type,
+  pub mutable: bool,
+  pub kind: VarKind,
+}
 
 #[derive(Debug, Clone)]
-pub enum Symbol {
-  Var(String, Type, bool),
-  Type(String, Type),
+pub enum Definition {
+  Symbol(Symbol),
   BlockStart,
   FuncStart,
 }
 
+fn next(array: &mut [uid]) -> uid {
+  let current = array.last_mut().unwrap();
+  let ret = *current;
+  *current += 1;
+  ret
+}
+
 #[derive(Debug, Clone)]
 pub struct SymbolTable {
-  syms: Vec<Symbol>,
+  syms: Vec<Definition>,
+  nesting: usize,
+  local_varno: Vec<uid>,
+  global_varno: Vec<uid>,
+  funcno: Vec<uid>,
 }
 
 impl SymbolTable {
-  fn define_var(&mut self, name: String, type_: Type, mutable: bool) {
-    self.syms.push(Symbol::Var(name, type_, mutable));
+  pub fn new() -> Self {
+    Self {
+      syms: vec![],
+      nesting: 0,
+      global_varno: vec![0],
+      local_varno: vec![0],
+      funcno: vec![0],
+    }
   }
 
-  fn define_type(&mut self, name: String, type_: Type) {
-    self.syms.push(Symbol::Type(name, type_));
+  fn define_symbol(
+    &mut self,
+    name: String,
+    type_: Type,
+    mutable: bool,
+  ) -> Result<VarKind> {
+    let kind = match type_ {
+      Type::Prim(_) | Type::Struct(_) => {
+        if self.nesting == 0 {
+          VarKind::Global(next(&mut self.global_varno))
+        } else {
+          VarKind::Local(next(&mut self.local_varno))
+        }
+      },
+      Type::StructDef(_) => {
+        if mutable {
+          return error().reason("Struct definition must be immutable");
+        }
+        VarKind::Undefined
+      },
+      Type::Function { .. } => {
+        if !mutable {
+          VarKind::Function(next(&mut self.funcno))
+        } else {
+          return error().reason("Function declaration must be immutable");
+        }
+      },
+      _ => VarKind::Undefined,
+    };
+    self.syms.push(Definition::Symbol(Symbol {
+      name,
+      type_,
+      mutable,
+      kind,
+    }));
+    Ok(kind)
+  }
+
+  fn define_param(&mut self, name: String, type_: Type) -> Result<VarKind> {
+    let kind = VarKind::Param(next(&mut self.local_varno));
+    self.syms.push(Definition::Symbol(Symbol {
+      name,
+      type_,
+      mutable: false,
+      kind,
+    }));
+    Ok(kind)
   }
 
   fn start_func(&mut self) {
-    self.syms.push(Symbol::FuncStart);
+    self.nesting += 1;
+    self.local_varno.push(0);
+    self.syms.push(Definition::FuncStart);
   }
 
   fn end_func(&mut self) {
+    self.nesting -= 1;
+    self.local_varno.pop();
     while !self.syms.is_empty() {
-      if let Some(Symbol::FuncStart) = self.syms.pop() {
+      if let Some(Definition::FuncStart) = self.syms.pop() {
         return;
       }
     }
@@ -41,34 +140,50 @@ impl SymbolTable {
   }
 
   fn start_block(&mut self) {
-    self.syms.push(Symbol::BlockStart);
+    self.syms.push(Definition::BlockStart);
   }
 
   fn end_block(&mut self) {
     while !self.syms.is_empty() {
-      if let Some(Symbol::BlockStart) = self.syms.pop() {
+      if let Some(Definition::BlockStart) = self.syms.pop() {
         return;
       }
     }
     unreachable!("Tried to exit global scope in symbol table")
   }
 
-  fn get_var(&self, name: &str) -> Result<(Type, bool)> {
+  fn find_symbol(&self, find_name: &str) -> Result<Symbol> {
+    let mut nesting = self.nesting;
+    println!("Looking for {find_name}, scope = {nesting}");
     for s in self.syms.iter().rev() {
-      if let Symbol::Var(name2, type_, mutable) = s {
-        if name == name2 {
-          return Ok((type_.clone(), *mutable));
-        }
-      }
+      match s {
+        Definition::Symbol(sym)
+          // Only search function local and global scope
+          if nesting == self.nesting || nesting == 0 => {
+          println!("{}, {:?}, {nesting}", sym.name, sym.type_);
+          if find_name == sym.name {
+            return Ok(sym.clone());
+          }
+        },
+        Definition::FuncStart => {
+          nesting -= 1;
+        },
+        _ => {},
+      };
     }
-    error().reason(format!("Identifier {name} is not defined"))
+    error().reason(format!("Symbol '{find_name}' is not defined"))
   }
 
   fn get_type(&self, name: &str) -> Result<Type> {
     for s in self.syms.iter().rev() {
-      if let Symbol::Type(name2, t) = s {
+      if let Definition::Symbol(Symbol {
+        name: name2,
+        type_: Type::StructDef(params),
+        ..
+      }) = s
+      {
         if name == name2 {
-          return Ok(t.clone());
+          return Ok(Type::Struct(params.clone()));
         }
       }
     }

src/semantic/types.rs

@@ -1,5 +1,6 @@
 use crate::{
-  semantic::SymbolTable, BinaryOp, Expression, ExpressionKind, Immediate, Parameter, Statement,
+  semantic::{Symbol, SymbolTable},
+  BinaryOp, Expression, ExpressionKind, Immediate, Parameter, Statement,
   StatementKind, UnaryOp,
 };
 
@@ -12,6 +13,7 @@ pub enum Type {
   Nothing,
   Prim(Primitive),
   Struct(Vec<Parameter>),
+  StructDef(Vec<Parameter>),
   Function {
     params: Vec<Type>,
     returns: Box<Type>,
@@ -54,7 +56,7 @@ impl Type {
       (t::Prim(a), t::Prim(b)) => {
         let p = Primitive::binary_op(*a, op, *b)?;
         Ok(t::Prim(p))
-      }
+      },
       _ => e,
     }
   }
@@ -69,392 +71,24 @@ impl Type {
     }
   }
 
-  fn coerce(expect: &Type, actual: &Type) -> Option<Type> {
+  pub fn coerce(expect: &Type, actual: &Type) -> Result<Type> {
     use Primitive as p;
     use Type::*;
+    let e = || {
+      error().reason(format!(
+        "Could not coerce type '{actual:?}' into '{expect:?}'"
+      ))
+    };
     match (expect, actual) {
-      (Ambiguous, Ambiguous) => None,
-      (Ambiguous, Prim(p::integer_ambiguous)) => Some(Prim(p::integer)),
-      (Ambiguous, Prim(p::real_ambiguous)) => Some(Prim(p::real)),
-      (Ambiguous, t) => Some(t.clone()),
+      (Ambiguous, Ambiguous) => e(),
+      (Ambiguous, Prim(p::integer_ambiguous)) => Ok(Prim(p::integer)),
+      (Ambiguous, Prim(p::real_ambiguous)) => Ok(Prim(p::real)),
+      (Ambiguous, t) => Ok(t.clone()),
       (Prim(p1), Prim(p2)) => {
         let (p1, p2) = Primitive::coerce_ambiguous(*p1, *p2);
-        if p1 != p2 {
-          None
-        } else {
-          Some(Type::Prim(p1))
-        }
-      }
-      _ => None,
-    }
-  }
-}
-
-pub fn typecheck(program: Vec<Statement>) -> Vec<Statement> {
-  use StatementKind as s;
-  let mut table = SymbolTable { syms: vec![] };
-  let mut ret = vec![];
-  for s in program {
-    let span = s.span;
-    ret.push(match statement(s.into(), &mut table) {
-      Ok(s) => *s,
-      Err(e) => Statement {
-        kind: s::Error(e),
-        span,
+        if p1 != p2 { e() } else { Ok(Type::Prim(p1)) }
       },
-    })
+      _ => e(),
+    }
   }
-  ret
-}
-
-fn statement(mut stmt: Box<Statement>, table: &mut SymbolTable) -> Result<Box<Statement>> {
-  use Primitive as p;
-  use StatementKind as s;
-  match stmt.kind {
-    s::Declaration {
-      name,
-      type_str,
-      value,
-      mutable,
-      ..
-    } => {
-      let type_expect = match type_str {
-        Some(ref s) => table.get_type(s).span(&stmt.span)?,
-        None => Type::Ambiguous,
-      };
-      let value = expression(value.into(), table)?;
-      let type_actual = Type::coerce(&type_expect, &value.type_).reason(format!(
-        "Expected type '{:?}', found type '{:?}'",
-        type_expect, value.type_
-      ))?;
-      // Check that structs are const
-      if let Type::Struct(_) = type_actual {
-        if mutable {
-          return error()
-            .reason("Struct declarations must be immutable")
-            .span(&stmt.span);
-        }
-        table.define_type(name.clone(), type_actual.clone());
-      }
-      // Check that functions are const
-      else if let Type::Function { .. } = type_actual {
-        if mutable {
-          return error()
-            .reason("Function declarations must be immutable")
-            .span(&stmt.span);
-        }
-        table.define_var(name.clone(), type_actual.clone(), false);
-      } else {
-        table.define_var(name.clone(), type_actual.clone(), mutable);
-      }
-      stmt.kind = s::Declaration {
-        name,
-        type_str,
-        type_actual,
-        value: *value,
-        mutable,
-      };
-    }
-    s::Assignment { name, value } => {
-      let (type_, mutable) = table.get_var(&name).span(&stmt.span)?;
-      // Check that it is mutable
-      if !mutable {
-        return error()
-          .reason(format!("Cannot assign to immutable '{}'", name))
-          .span(&stmt.span);
-      }
-      let value = *expression(value.into(), table)?;
-      // Check for correct type
-      if type_ != value.type_ {
-        return error().reason(format!(
-          "Attempted to assign '{:?}' to '{type_:?}'",
-          value.type_
-        ));
-      }
-      stmt.kind = s::Assignment { name, value };
-    }
-    s::If {
-      predicate,
-      block,
-      else_,
-    } => {
-      table.start_block();
-      let predicate = *expression(predicate.into(), table)?;
-      if predicate.type_ != Type::Prim(p::boolean) {
-        return error()
-          .reason(format!(
-            "Predicate of if statement must be a boolean, found {:?}",
-            predicate.type_
-          ))
-          .span(&predicate.span);
-      }
-      let mut new_block = vec![];
-      for stmt in block {
-        new_block.push(*statement(stmt.into(), table)?);
-      }
-      let else_ = if let Some(else_) = else_ {
-        Some(statement(else_, table)?)
-      } else {
-        None
-      };
-      stmt.kind = s::If {
-        predicate,
-        block: new_block,
-        else_,
-      };
-      table.end_block();
-    }
-    s::While { predicate, block } => {
-      table.start_block();
-      let predicate = *expression(predicate.into(), table)?;
-      if predicate.type_ != Type::Prim(p::boolean) {
-        return error()
-          .reason(format!(
-            "Predicate of while statement must be a boolean, found {:?}",
-            predicate.type_
-          ))
-          .span(&predicate.span);
-      }
-      let mut new_block = vec![];
-      for stmt in block {
-        new_block.push(*statement(stmt.into(), table)?);
-      }
-      stmt.kind = s::While {
-        predicate,
-        block: new_block,
-      };
-      table.end_block();
-    }
-    s::Print(e) => {
-      stmt.kind = s::Print(*expression(e.into(), table)?);
-    }
-    s::Expression(mut e) => {
-      use ExpressionKind as e;
-      let is_func = if let e::Function { params, .. } = &mut e.kind {
-        // TODO: start/end function instead
-        table.start_block();
-        for p in params {
-          p.type_actual = table.get_type(&p.type_str)?;
-          table.define_var(p.name.clone(), p.type_actual.clone(), false);
-        }
-        true
-      } else {
-        false
-      };
-      stmt.kind = s::Expression(*expression(e.into(), table)?);
-      if is_func {
-        table.end_block();
-      }
-    }
-    s::Block(block) => {
-      table.start_block();
-      let mut new_block = vec![];
-      for stmt in block {
-        new_block.push(*statement(stmt.into(), table)?);
-      }
-      stmt.kind = s::Block(new_block);
-      table.end_block();
-    }
-    s::Error(e) => return Err(e),
-  }
-  Ok(stmt)
-}
-
-fn expression(mut expr: Box<Expression>, table: &SymbolTable) -> Result<Box<Expression>> {
-  use ExpressionKind as e;
-  use Immediate as i;
-  use Primitive as p;
-  let type_ = match expr.kind {
-    e::Immediate(ref i) => Type::Prim(match i {
-      i::Integer(_) => p::integer_ambiguous,
-      i::Real(_) => p::real_ambiguous,
-      i::String(_) => p::string,
-      i::Boolean(_) => p::boolean,
-    }),
-    e::Identifier(ref i) => table.get_var(i)?.0,
-    e::Binary { op, left, right } => {
-      let left = expression(left, table)?;
-      let right = expression(right, table)?;
-      let type_ = Type::binary_op(&left.type_, op, &right.type_)?;
-      expr.kind = e::Binary { left, right, op };
-      type_
-    }
-    e::Unary { op, child } => {
-      let child = expression(child, table)?;
-      let type_ = Type::unary_op(op, &child.type_)?;
-      expr.kind = e::Unary { child, op };
-      type_
-    }
-    e::Parenthesis(inner) => {
-      let inner = expression(inner, table)?;
-      let type_ = inner.type_.clone();
-      expr.kind = e::Parenthesis(inner);
-      type_
-    }
-    e::Function {
-      mut params,
-      returns_str,
-      mut returns_actual,
-      body,
-    } => {
-      for p in &mut params {
-        p.type_actual = table.get_type(&p.type_str).span(&expr.span)?;
-      }
-      returns_actual = match &returns_str {
-        Some(s) => table.get_type(s).span(&expr.span)?,
-        None => Type::Nothing,
-      };
-      expr.kind = e::Function {
-        params: params.clone(),
-        returns_str,
-        returns_actual: returns_actual.clone(),
-        body,
-      };
-      Type::Function {
-        params: params.into_iter().map(|p| p.type_actual).collect(),
-        returns: returns_actual.into(),
-      }
-    }
-    e::Call { callee, mut args } => {
-      let callee = expression(callee, table)?;
-      // Check that this is actually a function
-      let Type::Function {
-        ref params,
-        ref returns,
-      } = callee.type_
-      else {
-        return error()
-          .reason(format!("Cannot call type {:?}", callee.type_))
-          .span(&callee.span);
-      };
-      // Check for correct number of args
-      if params.len() != args.len() {
-        return error()
-          .reason(format!(
-            "Wrong number of arguments, function expects {}, found {}",
-            params.len(),
-            args.len()
-          ))
-          .span(&callee.span);
-      }
-      // Check for correct arg types
-      for (expect, actual) in params.iter().zip(args.iter_mut()) {
-        *actual = *expression(actual.clone().into(), table)?;
-        let coerced_type = Type::coerce(expect, &actual.type_);
-        println!("{:?}, {:?}, {coerced_type:?}", expect, actual.type_);
-        if let Some(t) = coerced_type {
-          actual.type_ = t;
-        } else {
-          return error()
-            .reason(format!(
-              "Expected type {expect:?}, found {:?}",
-              actual.type_
-            ))
-            .span(&actual.span);
-        }
-      }
-      let returns = *returns.clone();
-      expr.kind = e::Call { callee, args };
-      returns
-    }
-    e::Struct(mut params) => {
-      for p in &mut params {
-        p.type_actual = table.get_type(&p.type_str).span(&expr.span)?;
-      }
-      expr.kind = e::Struct(params.clone());
-      Type::Struct(params)
-    }
-    e::StructLiteral { name, args } => {
-      let type_ = table.get_type(&name).span(&expr.span)?;
-      let Type::Struct(params) = type_ else {
-        return error().reason(format!(
-          "Cannot construct type {:?} as struct literal",
-          type_
-        ));
-      };
-      if args.len() != params.len() {
-        return error().reason(format!(
-          "Incorrect number of parameters for struct '{}'; expected {}, \
-           found {}",
-          name,
-          params.len(),
-          args.len()
-        ));
-      }
-      // TODO out of order params
-      let mut new_args = vec![];
-      for (
-        (argname, argexpr),
-        Parameter {
-          name: pname,
-          type_actual: ptype,
-          ..
-        },
-      ) in args.iter().zip(params.iter())
-      {
-        if argname != pname {
-          return error()
-            .reason(format!(
-              "In struct literal, expected parameter '{pname}', found \
-               '{argname}'"
-            ))
-            .span(&argexpr.span);
-        }
-        let argspan = argexpr.span;
-        let mut arg = *expression(argexpr.clone().into(), table)
-          .trace_span(expr.span, "while parsing struct literal")?;
-        let coerced_type = Type::coerce(ptype, &arg.type_);
-        if let Some(t) = coerced_type {
-          arg.type_ = t;
-        } else {
-          return error()
-            .reason(format!(
-              "In struct literal, expected type '{ptype:?}', found '{:?}",
-              arg.type_,
-            ))
-            .span(&argspan);
-        }
-        new_args.push((argname.clone(), arg));
-      }
-      expr.kind = e::StructLiteral {
-        name,
-        args: new_args,
-      };
-      Type::Struct(params)
-    }
-    e::Field { namespace, field } => {
-      let namespace = expression(namespace, table)?;
-      // Check that namespace is struct
-      // TODO: fields in other types
-      let Type::Struct(ref params) = namespace.type_ else {
-        return error()
-          .reason(format!("Type {:?} does not have fields", namespace.type_))
-          .span(&namespace.span);
-      };
-      // Check that field is identifier
-      // TODO: tuple fields?
-      let e::Identifier(ref name) = field.kind else {
-        return error()
-          .reason("Field must be an identifier")
-          .span(&field.span);
-      };
-      let mut type_ = None;
-      for p in params {
-        if &p.name == name {
-          type_ = Some(p.type_actual.clone());
-          break;
-        }
-      }
-      let type_ = type_
-        .reason(format!(
-          "Type {:?} does not contain field {}",
-          namespace, name
-        ))
-        .span(&field.span)?;
-      expr.kind = e::Field { namespace, field };
-      type_
-    }
-  };
-  expr.type_ = type_;
-  Ok(expr)
 }