add rudimentary type inference, todo: args

Cargo.lock

@@ -156,9 +156,9 @@ checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
 [[package]]
 name = "clap"
-version = "4.3.0"
+version = "4.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "93aae7a4192245f70fe75dd9157fc7b4a5bf53e88d30bd4396f7d8f9284d5acc"
+checksum = "b4ed2379f8603fa2b7509891660e802b88c70a79a6427a70abb5968054de2c28"
 dependencies = [
  "clap_builder",
  "clap_derive",
@@ -167,9 +167,9 @@ dependencies = [
 
 [[package]]
 name = "clap_builder"
-version = "4.3.0"
+version = "4.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4f423e341edefb78c9caba2d9c7f7687d0e72e89df3ce3394554754393ac3990"
+checksum = "72394f3339a76daf211e57d4bcb374410f3965dcc606dd0e03738c7888766980"
 dependencies = [
  "anstream",
  "anstyle",
@@ -180,9 +180,9 @@ dependencies = [
 
 [[package]]
 name = "clap_derive"
-version = "4.3.0"
+version = "4.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "191d9573962933b4027f932c600cd252ce27a8ad5979418fe78e43c07996f27b"
+checksum = "59e9ef9a08ee1c0e1f2e162121665ac45ac3783b0f897db7244ae75ad9a8f65b"
 dependencies = [
  "heck",
  "proc-macro2",
@@ -520,12 +520,9 @@ dependencies = [
 
 [[package]]
 name = "log"
-version = "0.4.17"
+version = "0.4.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "abb12e687cfb44aa40f41fc3978ef76448f9b6038cad6aef4259d3c095a2382e"
-dependencies = [
- "cfg-if",
-]
+checksum = "518ef76f2f87365916b142844c16d8fefd85039bc5699050210a7778ee1cd1de"
 
 [[package]]
 name = "logos"
@@ -610,9 +607,9 @@ dependencies = [
 
 [[package]]
 name = "once_cell"
-version = "1.17.1"
+version = "1.17.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b7e5500299e16ebb147ae15a00a942af264cf3688f47923b8fc2cd5858f23ad3"
+checksum = "9670a07f94779e00908f3e686eab508878ebb390ba6e604d3a284c00e8d0487b"
 
 [[package]]
 name = "overload"

Cargo.toml

@@ -12,7 +12,7 @@ categories = ["compilers"]
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-clap = { version = "4.3.0", features = ["derive"] }
+clap = { version = "4.3.1", features = ["derive"] }
 color-eyre = "0.6.2"
 itertools = "0.10.5"
 lalrpop-util = { version = "0.20.0", features = ["lexer"] }

src/ast/mod.rs

@@ -51,17 +51,25 @@ pub enum TypeExp {
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub enum LiteralValue {
     String(String),
-    Integer(String),
+    Integer {
+        value: String,
+        bits: Option<u32>,
+        signed: Option<bool>,
+    },
     Boolean(bool),
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub enum Expression {
     Literal(LiteralValue),
-    Variable(Spanned<String>),
+    Variable {
+        name: Spanned<String>,
+        value_type: Option<TypeExp>,
+    },
     Call {
         function: String,
         args: Vec<Box<Self>>,
+        value_type: Option<TypeExp>,
     },
     BinaryOp(Box<Self>, OpCode, Box<Self>),
 }
@@ -128,12 +136,13 @@ pub enum Statement {
     Let {
         name: String,
         value: Box<Expression>,
-        type_name: Option<TypeExp>,
+        value_type: Option<TypeExp>,
         span: (usize, usize),
     },
     Mutate {
         name: String,
         value: Box<Expression>,
+        value_type: Option<TypeExp>,
         span: (usize, usize),
     },
     If {

src/codegen.rs

@@ -261,7 +261,7 @@ impl<'ctx> CodeGen<'ctx> {
             if let Statement::Return(_) = statement {
                 has_return = true
             }
-            self.compile_statement(function, func, statement, &mut variables, &mut types)?;
+            self.compile_statement(func, statement, &mut variables, &mut types)?;
         }
 
         if !has_return {
@@ -271,41 +271,8 @@ impl<'ctx> CodeGen<'ctx> {
         Ok(())
     }
 
-    fn find_expr_type(&self, expr: &Expression, variables: &Variables<'ctx>) -> Option<TypeExp> {
-        match expr {
-            Expression::Literal(x) => match x {
-                LiteralValue::String(_s) => {
-                    todo!("make internal string struct")
-                    /* todo: internal string structure here
-                        Some(
-                        self.context
-                            .i8_type()
-                            .array_type(s.bytes().len() as u32 + 1)
-                            .as_basic_type_enum(),
-                    ) */
-                }
-                LiteralValue::Integer(_) => Some(TypeExp::Integer {
-                    bits: 32,
-                    signed: true,
-                }),
-                LiteralValue::Boolean(_) => Some(TypeExp::Boolean),
-            },
-            Expression::Variable(x) => variables.get(&x.value).cloned().map(|x| x.type_exp),
-            Expression::Call { function, args: _ } => {
-                self.functions.get(function).unwrap().clone().1
-            }
-            Expression::BinaryOp(lhs, op, rhs) => match op {
-                //OpCode::Eq | OpCode::Ne => Some(TypeExp::Boolean),
-                _ => self
-                    .find_expr_type(lhs, variables)
-                    .or_else(|| self.find_expr_type(rhs, variables)),
-            },
-        }
-    }
-
     fn compile_statement(
         &self,
-        function: &Function,
         function_value: FunctionValue,
         statement: &Statement,
         // value, assignments
@@ -317,22 +284,11 @@ impl<'ctx> CodeGen<'ctx> {
             Statement::Let {
                 name,
                 value,
-                type_name,
+                value_type: _,
                 ..
             } => {
-                let type_hint = if let Some(type_name) = type_name {
-                    type_name.clone()
-                } else {
-                    let type_exp = self
-                        .find_expr_type(value, variables)
-                        .expect("type should be found");
-                    let ty = self.get_llvm_type(&type_exp)?;
-                    types.insert(type_exp.clone(), ty);
-                    type_exp
-                };
-
                 let (value, value_type) = self
-                    .compile_expression(value, variables, types, Some(type_hint))?
+                    .compile_expression(value, variables, types)?
                     .expect("should have result");
 
                 if !types.contains_key(&value_type) {
@@ -352,11 +308,8 @@ impl<'ctx> CodeGen<'ctx> {
                 );
             }
             Statement::Mutate { name, value, .. } => {
-                let var = variables.get(name).cloned().expect("variable should exist");
-                let type_hint = var.type_exp;
-
                 let (value, value_type) = self
-                    .compile_expression(value, variables, types, Some(type_hint))?
+                    .compile_expression(value, variables, types)?
                     .expect("should have result");
 
                 let var = variables.get_mut(name).expect("variable should exist");
@@ -367,14 +320,8 @@ impl<'ctx> CodeGen<'ctx> {
             }
             Statement::Return(ret) => {
                 if let Some(ret) = ret {
-                    let type_hint = self
-                        .functions
-                        .get(&function.name)
-                        .expect("function should exist")
-                        .clone()
-                        .1;
                     let (value, _value_type) = self
-                        .compile_expression(ret, variables, types, type_hint)?
+                        .compile_expression(ret, variables, types)?
                         .expect("should have result");
                     self.builder.build_return(Some(&value));
                 } else {
@@ -386,9 +333,8 @@ impl<'ctx> CodeGen<'ctx> {
                 body,
                 else_body,
             } => {
-                let type_hint = self.find_expr_type(condition, variables);
                 let (condition, _cond_type) = self
-                    .compile_expression(condition, variables, types, type_hint)?
+                    .compile_expression(condition, variables, types)?
                     .expect("should produce a value");
 
                 let mut if_block = self.context.append_basic_block(function_value, "if");
@@ -408,7 +354,7 @@ impl<'ctx> CodeGen<'ctx> {
                 let mut variables_if = variables.clone();
                 self.builder.position_at_end(if_block);
                 for s in body {
-                    self.compile_statement(function, function_value, s, &mut variables_if, types)?;
+                    self.compile_statement(function_value, s, &mut variables_if, types)?;
                 }
                 self.builder.build_unconditional_branch(merge_block);
                 if_block = self.builder.get_insert_block().unwrap(); // update for phi
@@ -418,13 +364,7 @@ impl<'ctx> CodeGen<'ctx> {
                     self.builder.position_at_end(else_block);
 
                     for s in else_body {
-                        self.compile_statement(
-                            function,
-                            function_value,
-                            s,
-                            &mut variables_else,
-                            types,
-                        )?;
+                        self.compile_statement(function_value, s, &mut variables_else, types)?;
                     }
                     self.builder.build_unconditional_branch(merge_block);
                     else_block = self.builder.get_insert_block().unwrap(); // update for phi
@@ -489,16 +429,20 @@ impl<'ctx> CodeGen<'ctx> {
         expr: &Expression,
         variables: &mut Variables<'ctx>,
         types: &mut TypeStorage<'ctx>,
-        type_hint: Option<TypeExp>,
     ) -> Result<Option<(BasicValueEnum<'ctx>, TypeExp)>> {
         Ok(match expr {
-            Expression::Variable(term) => Some(self.compile_variable(&term.value, variables)?),
-            Expression::Literal(term) => Some(self.compile_literal(term, type_hint)?),
-            Expression::Call { function, args } => {
-                self.compile_call(function, args, variables, types)?
-            }
+            Expression::Variable {
+                name,
+                value_type: _,
+            } => Some(self.compile_variable(&name.value, variables)?),
+            Expression::Literal(term) => Some(self.compile_literal(term)?),
+            Expression::Call {
+                function,
+                args,
+                value_type,
+            } => self.compile_call(function, args, variables, types, value_type.clone())?,
             Expression::BinaryOp(lhs, op, rhs) => {
-                Some(self.compile_binary_op(lhs, op, rhs, variables, types, type_hint)?)
+                Some(self.compile_binary_op(lhs, op, rhs, variables, types)?)
             }
         })
     }
@@ -509,20 +453,16 @@ impl<'ctx> CodeGen<'ctx> {
         args: &[Box<Expression>],
         variables: &mut Variables<'ctx>,
         types: &mut TypeStorage<'ctx>,
+        value_type: Option<TypeExp>,
     ) -> Result<Option<(BasicValueEnum<'ctx>, TypeExp)>> {
         info!("compiling fn call: func_name={}", func_name);
         let function = self.module.get_function(func_name).expect("should exist");
-        let func_info = self
-            .functions
-            .get(func_name)
-            .cloned()
-            .expect("should exist");
 
         let mut value_args: Vec<BasicMetadataValueEnum> = Vec::with_capacity(args.len());
 
-        for (arg, arg_type) in args.iter().zip(func_info.0.iter()) {
+        for arg in args.iter() {
             let (res, _res_type) = self
-                .compile_expression(arg, variables, types, Some(arg_type.clone()))?
+                .compile_expression(arg, variables, types)?
                 .expect("should have result");
             value_args.push(res.into());
         }
@@ -533,10 +473,7 @@ impl<'ctx> CodeGen<'ctx> {
             .try_as_basic_value();
 
         Ok(match result {
-            Either::Left(val) => Some((
-                val,
-                func_info.1.expect("should have ret type info if returns"),
-            )),
+            Either::Left(val) => Some((val, value_type.unwrap())),
             Either::Right(_) => None,
         })
     }
@@ -548,13 +485,12 @@ impl<'ctx> CodeGen<'ctx> {
         rhs: &Expression,
         variables: &mut Variables<'ctx>,
         types: &mut TypeStorage<'ctx>,
-        type_hint: Option<TypeExp>,
     ) -> Result<(BasicValueEnum<'ctx>, TypeExp)> {
         let (lhs, lhs_type) = self
-            .compile_expression(lhs, variables, types, type_hint.clone())?
+            .compile_expression(lhs, variables, types)?
             .expect("should have result");
         let (rhs, _rhs_type) = self
-            .compile_expression(rhs, variables, types, type_hint)?
+            .compile_expression(rhs, variables, types)?
             .expect("should have result");
 
         let lhs = lhs.into_int_value();
@@ -593,11 +529,7 @@ impl<'ctx> CodeGen<'ctx> {
         Ok((result.as_basic_value_enum(), res_type))
     }
 
-    pub fn compile_literal(
-        &self,
-        term: &LiteralValue,
-        type_hint: Option<TypeExp>,
-    ) -> Result<(BasicValueEnum<'ctx>, TypeExp)> {
+    pub fn compile_literal(&self, term: &LiteralValue) -> Result<(BasicValueEnum<'ctx>, TypeExp)> {
         let value = match term {
             LiteralValue::String(_s) => {
                 todo!()
@@ -614,28 +546,20 @@ impl<'ctx> CodeGen<'ctx> {
                     .as_basic_value_enum(),
                 TypeExp::Boolean,
             ),
-            LiteralValue::Integer(v) => {
-                if let Some(type_hint) = type_hint {
-                    (
-                        self.get_llvm_type(&type_hint)?
-                            .into_int_type()
-                            .const_int(v.parse().unwrap(), false)
-                            .as_basic_value_enum(),
-                        type_hint,
-                    )
-                } else {
-                    let type_exp = TypeExp::Integer {
-                        bits: 32,
-                        signed: true,
-                    };
-                    (
-                        self.get_llvm_type(&type_exp)?
-                            .into_int_type()
-                            .const_int(v.parse().unwrap(), false)
-                            .as_basic_value_enum(),
-                        type_exp,
-                    )
-                }
+            LiteralValue::Integer {
+                value,
+                bits,
+                signed,
+            } => {
+                let bits = bits.unwrap_or(32);
+                let signed = signed.unwrap_or(true);
+                (
+                    self.context
+                        .custom_width_int_type(bits)
+                        .const_int(value.parse().unwrap(), false)
+                        .as_basic_value_enum(),
+                    TypeExp::Integer { bits, signed },
+                )
             }
         };
 

src/grammar.lalrpop

@@ -94,9 +94,12 @@ TypeInfo: ast::TypeExp =  {
 
 // statements not including function definitions
 BasicStatement: ast::Statement = {
-    <lo:@L> "let" <i:"identifier"> <t:TypeInfo?> "=" <e:Expr> ";" <hi:@R> => ast::Statement::Let { name: i, value: e, type_name: t, span: (lo, hi) },
-    <lo:@L> <i:"identifier"> "=" <e:Expr> ";" <hi:@R>  => ast::Statement::Mutate { name: i, value: e, span: (lo, hi) },
-    "if" <cond:Expr> "{" <s:Statements> "}" <e:ElseExpr?> => ast::Statement::If { condition: cond, body: s, else_body: e},
+    <lo:@L> "let" <i:"identifier"> <t:TypeInfo?> "=" <e:Expr> ";" <hi:@R> =>
+            ast::Statement::Let { name: i, value: e, value_type: t, span: (lo, hi) },
+    <lo:@L> <i:"identifier"> "=" <e:Expr> ";" <hi:@R> =>
+            ast::Statement::Mutate { name: i, value: e, span: (lo, hi), value_type: None },
+    "if" <cond:Expr> "{" <s:Statements> "}" <e:ElseExpr?> =>
+            ast::Statement::If { condition: cond, body: s, else_body: e},
     "return" <e:Expr?> ";" => ast::Statement::Return(e),
 };
 
@@ -137,15 +140,22 @@ Expr4 = Tier<Level3_Op, Term>;
 
 // Terms: variables, literals, calls
 Term: Box<ast::Expression> = {
-    <lo:@L> <i:"identifier"> <hi:@R> => Box::new(ast::Expression::Variable(Spanned::new(i, (lo, hi)))),
+    <lo:@L> <i:"identifier"> <hi:@R> => Box::new(ast::Expression::Variable {
+        name: Spanned::new(i, (lo, hi)),
+        value_type: None
+    }),
     <n:Number> => Box::new(ast::Expression::Literal(n)),
     <n:StringLit> => Box::new(ast::Expression::Literal(n)),
     <n:BoolLiteral> => Box::new(ast::Expression::Literal(n)),
-    <i:"identifier"> "(" <values:Comma<Term>> ")" => Box::new(ast::Expression::Call { function: i, args: values}),
+    <i:"identifier"> "(" <values:Comma<Term>> ")" => Box::new(ast::Expression::Call { function: i, args: values, value_type: None }),
     "(" <Term> ")"
 };
 
-Number: ast::LiteralValue = <n:"int literal"> => ast::LiteralValue::Integer(n);
+Number: ast::LiteralValue = <n:"int literal"> => ast::LiteralValue::Integer {
+    value: n,
+    bits: None,
+    signed: None
+};
 
 StringLit: ast::LiteralValue = <n:"string literal"> => ast::LiteralValue::String(n[1..(n.len()-1)].to_string());
 

src/main.rs

@@ -14,6 +14,7 @@ pub mod check;
 pub mod codegen;
 pub mod lexer;
 pub mod tokens;
+pub mod type_analysis;
 
 lalrpop_mod!(pub grammar);
 
@@ -99,15 +100,17 @@ fn main() -> Result<()> {
             let code = fs::read_to_string(&input)?;
             let lexer = Lexer::new(code.as_str());
             let parser = grammar::ProgramParser::new();
-            let ast = parser.parse(lexer)?;
+            let mut ast = parser.parse(lexer)?;
+            type_analysis::type_inference(&mut ast);
             let program = ProgramData::new(&input, &code);
             check_program(&program, &ast);
         }
         Commands::Ast { input } => {
-            let code = fs::read_to_string(&input)?;
+            let code = fs::read_to_string(input)?;
             let lexer = Lexer::new(code.as_str());
             let parser = grammar::ProgramParser::new();
-            let ast = parser.parse(lexer)?;
+            let mut ast = parser.parse(lexer)?;
+            type_analysis::type_inference(&mut ast);
             println!("{ast:#?}");
         }
         Commands::Compile {
@@ -119,7 +122,8 @@ fn main() -> Result<()> {
             let code = fs::read_to_string(&input)?;
             let lexer = Lexer::new(code.as_str());
             let parser = grammar::ProgramParser::new();
-            let ast: Program = parser.parse(lexer)?;
+            let mut ast: Program = parser.parse(lexer)?;
+            type_analysis::type_inference(&mut ast);
 
             let program = ProgramData::new(&input, &code);
 

src/type_analysis.rs

@@ -0,0 +1,276 @@
+use std::collections::HashMap;
+
+use tracing::{info, warn};
+
+use crate::ast::{self, Expression, Function, Statement, TypeExp};
+
+pub fn type_inference(ast: &mut ast::Program) {
+    for statement in ast.statements.iter_mut() {
+        if let Statement::Function(function) = statement {
+            let ret_type = function.return_type.clone();
+            let mut var_cache: HashMap<String, TypeExp> = HashMap::new();
+
+            if let Some(ret_type) = &ret_type {
+                let ret_type_exp = fn_return_type(function);
+
+                if let Some(exp) = ret_type_exp {
+                    set_expression_type(exp, ret_type, &mut var_cache);
+                }
+            }
+
+            update_statements(&mut function.body, &mut var_cache);
+        }
+    }
+}
+
+fn update_statements(statements: &mut [Statement], var_cache: &mut HashMap<String, TypeExp>) {
+    let mut var_cache = var_cache.clone();
+
+    {
+        let mut let_or_mut: Vec<&mut Statement> = statements
+            .iter_mut()
+            .filter(|x| matches!(x, Statement::Let { .. } | Statement::Mutate { .. }))
+            .collect();
+
+        // process mutate first
+        for st in let_or_mut.iter_mut() {
+            if let Statement::Mutate {
+                name,
+                value,
+                value_type,
+                ..
+            } = st
+            {
+                if let Some(value_type) = value_type {
+                    // todo: check types matches?
+                    var_cache.insert(name.clone(), value_type.clone());
+                    set_expression_type(value, value_type, &mut var_cache);
+                } else {
+                    // evalue the value expr first to find a possible type.
+                    if var_cache.contains_key(name) {
+                        *value_type = var_cache.get(name).cloned();
+                        let mut env = Some(value_type.clone().unwrap());
+                        set_exp_types_from_cache(value, &mut var_cache, &mut env);
+                    } else {
+                        // no type info?
+                    }
+                }
+            }
+        }
+
+        // we need to process lets with a specified type first.
+        for st in let_or_mut.iter_mut() {
+            if let Statement::Let {
+                name,
+                value,
+                value_type,
+                ..
+            } = st
+            {
+                if let Some(value_type) = value_type {
+                    // todo: check types matches?
+                    var_cache.insert(name.clone(), value_type.clone());
+                    set_expression_type(value, value_type, &mut var_cache);
+                } else {
+                    // evalue the value expr first to find a possible type.
+                    if var_cache.contains_key(name) {
+                        *value_type = var_cache.get(name).cloned();
+                        let mut env = Some(value_type.clone().unwrap());
+                        set_exp_types_from_cache(value, &mut var_cache, &mut env);
+                    } else {
+                        // no type info?
+                    }
+                }
+            }
+        }
+    }
+
+    for st in statements.iter_mut() {
+        match st {
+            Statement::Let {
+                name,
+                value_type,
+                value,
+                ..
+            } => {
+                // infer type if let has no type
+                if value_type.is_none() {
+                    // evalue the value expr first to find a possible type.
+                    let mut env = None;
+                    set_exp_types_from_cache(value, &mut var_cache, &mut env);
+
+                    // try to find if it was set on the cache
+                    if var_cache.contains_key(name) {
+                        *value_type = var_cache.get(name).cloned();
+                        set_expression_type(value, value_type.as_ref().unwrap(), &mut var_cache);
+                    } else {
+                        // what here? no let type, no cache
+                        println!("no cache let found")
+                    }
+                }
+            }
+            Statement::Mutate {
+                name,
+                value_type,
+                value,
+                ..
+            } => {
+                if let Some(value_type) = value_type {
+                    // todo: check types matches?
+                    var_cache.insert(name.clone(), value_type.clone());
+                    set_expression_type(value, value_type, &mut var_cache);
+                } else {
+                    // evalue the value expr first to find a possible type.
+                    if var_cache.contains_key(name) {
+                        *value_type = var_cache.get(name).cloned();
+                        let mut env = Some(value_type.clone().unwrap());
+                        set_exp_types_from_cache(value, &mut var_cache, &mut env);
+                    } else {
+                        // no type info?
+                    }
+                }
+            }
+            Statement::If {
+                condition,
+                body,
+                else_body,
+            } => {
+                let mut env = None;
+                set_exp_types_from_cache(condition, &mut var_cache, &mut env);
+                update_statements(body, &mut var_cache);
+                if let Some(else_body) = else_body {
+                    update_statements(else_body, &mut var_cache);
+                }
+            }
+            Statement::Return(exp) => {
+                if let Some(exp) = exp {
+                    let mut env = None;
+                    set_exp_types_from_cache(exp, &mut var_cache, &mut env);
+                }
+            }
+            Statement::Function(_) => unreachable!(),
+            Statement::Struct(_) => unreachable!(),
+        }
+    }
+}
+
+fn fn_return_type(func: &mut Function) -> Option<&mut Box<Expression>> {
+    for st in func.body.iter_mut() {
+        if let Statement::Return(r) = st {
+            return r.as_mut();
+        }
+    }
+    None
+}
+
+// set variables using the cache
+fn set_exp_types_from_cache(
+    exp: &mut Expression,
+    var_cache: &mut HashMap<String, TypeExp>,
+    env: &mut Option<TypeExp>,
+) {
+    match exp {
+        Expression::Variable { name, value_type } => {
+            let name = name.value.clone();
+            if let Some(value_type) = value_type {
+                // todo: check types matches?
+                var_cache.insert(name, value_type.clone());
+            } else if var_cache.contains_key(&name) {
+                *value_type = var_cache.get(&name).cloned();
+                if env.is_none() {
+                    *env = value_type.clone();
+                }
+            }
+        }
+        Expression::BinaryOp(lhs, op, rhs) => match op {
+            ast::OpCode::Eq | ast::OpCode::Ne => {}
+            _ => {
+                set_exp_types_from_cache(lhs, var_cache, env);
+                set_exp_types_from_cache(rhs, var_cache, env);
+            }
+        },
+        Expression::Literal(lit) => match lit {
+            ast::LiteralValue::String(_) => {
+                warn!("found string, unimplemented")
+            }
+            ast::LiteralValue::Integer { bits, signed, .. } => {
+                if let Some(TypeExp::Integer {
+                    bits: t_bits,
+                    signed: t_signed,
+                }) = env
+                {
+                    *bits = Some(*t_bits);
+                    *signed = Some(*t_signed);
+                }
+            }
+            ast::LiteralValue::Boolean(_) => {
+                warn!("found bool, unimplemented")
+            }
+        },
+        Expression::Call {
+            function: _,
+            args: _,
+            value_type,
+        } => {
+            match value_type {
+                Some(value_type) => *env = Some(value_type.clone()),
+                None => {
+                    if env.is_some() {
+                        *value_type = env.clone();
+                    }
+                }
+            }
+            // TODO: infer args based on function args!
+        }
+    }
+}
+
+fn set_expression_type(
+    exp: &mut Expression,
+    expected_type: &TypeExp,
+    var_cache: &mut HashMap<String, TypeExp>,
+) {
+    match exp {
+        Expression::Variable { name, value_type } => {
+            // if needed?
+            if value_type.is_none() {
+                *value_type = Some(expected_type.clone());
+            }
+            if !var_cache.contains_key(&name.value) {
+                var_cache.insert(name.value.clone(), expected_type.clone());
+            }
+        }
+        Expression::BinaryOp(lhs, op, rhs) => match op {
+            ast::OpCode::Eq | ast::OpCode::Ne => {}
+            _ => {
+                set_expression_type(lhs, expected_type, var_cache);
+                set_expression_type(rhs, expected_type, var_cache);
+            }
+        },
+        Expression::Literal(lit) => match lit {
+            ast::LiteralValue::String(_) => {
+                warn!("found string, unimplemented")
+            }
+            ast::LiteralValue::Integer { bits, signed, .. } => {
+                if let TypeExp::Integer {
+                    bits: t_bits,
+                    signed: t_signed,
+                } = expected_type
+                {
+                    *bits = Some(*t_bits);
+                    *signed = Some(*t_signed);
+                }
+            }
+            ast::LiteralValue::Boolean(_) => {
+                warn!("found bool, unimplemented")
+            }
+        },
+        Expression::Call {
+            function: _,
+            args: _,
+            value_type,
+        } => {
+            *value_type = Some(expected_type.clone());
+        }
+    }
+}