Read return and function name from signature

examples/reid/easy.reid

@@ -1,10 +1,5 @@
 // Arithmetic, function calls and imports!
 
 fn main() {
-    let test = 9;
-    let simpleAdd = 2 + 2;
-    let simpleMult = 7 * 2;
-    let arithmetic = 3 + 2 * 5 + 1 * 2;
-
-    return arithmetic + simpleMult * arithmetic;
+    return 5;
 }

src/codegen/llvm.rs

@@ -5,6 +5,8 @@ use llvm_sys::{
     core::*, prelude::*, LLVMBasicBlock, LLVMBuilder, LLVMContext, LLVMModule, LLVMType, LLVMValue,
 };
 
+use crate::ast;
+
 fn into_cstring<T: Into<String>>(value: T) -> CString {
     let string = value.into();
     unsafe { CString::from_vec_with_nul_unchecked((string + "\0").into_bytes()) }
@@ -92,7 +94,7 @@ pub struct IRFunction<'a, 'b> {
 }
 
 impl<'a, 'b> IRFunction<'a, 'b> {
-    pub fn new(module: &'b mut IRModule<'a>) -> IRFunction<'a, 'b> {
+    pub fn new(name: &String, module: &'b mut IRModule<'a>) -> IRFunction<'a, 'b> {
         unsafe {
             // TODO, fix later!
 
@@ -102,8 +104,7 @@ impl<'a, 'b> IRFunction<'a, 'b> {
             let func_type =
                 LLVMFunctionType(return_type, argts.as_mut_ptr(), argts.len() as u32, 0);
 
-            let function =
-                LLVMAddFunction(module.module, into_cstring("testfunc").as_ptr(), func_type);
+            let function = LLVMAddFunction(module.module, into_cstring(name).as_ptr(), func_type);
 
             IRFunction {
                 module,
@@ -156,15 +157,20 @@ pub struct IRValue {
 }
 
 impl IRValue {
-    pub fn const_i32(value: i32, block: &mut IRBlock) -> Self {
+    pub fn from_literal(literal: &ast::Literal, block: &mut IRBlock) -> Self {
+        use ast::Literal;
+        match literal {
+            Literal::I32(v) => {
                 let ir_type = IRType::I32;
                 unsafe {
                     let ir_value = LLVMConstInt(
                         ir_type.in_context(block.function.module.context),
-                mem::transmute(3 as i64),
+                        mem::transmute(*v as i64),
                         1,
                     );
                     return IRValue { ir_type, ir_value };
                 }
             }
+        };
+    }
 }

src/codegen/mod.rs

@@ -2,7 +2,10 @@ mod llvm;
 
 use llvm::{IRBlock, IRContext, IRFunction, IRModule, IRValue};
 
-use crate::{ast::FunctionDefinition, TopLevelStatement};
+use crate::{
+    ast::{Block, Expression, ExpressionKind, FunctionDefinition},
+    TopLevelStatement,
+};
 
 #[derive(thiserror::Error, Debug)]
 pub enum Error {}
@@ -34,9 +37,31 @@ impl TopLevelStatement {
 
 impl FunctionDefinition {
     fn codegen(&self, module: &mut IRModule) {
-        let mut function = IRFunction::new(module);
-        let mut block = IRBlock::new(&mut function);
-        let value = IRValue::const_i32(3, &mut block);
+        let FunctionDefinition(signature, block, _) = self;
+        let mut function = IRFunction::new(&signature.name, module);
+        block.codegen(&mut function)
+    }
+}
+
+impl Block {
+    fn codegen(&self, function: &mut IRFunction) {
+        let mut block = IRBlock::new(function);
+
+        if let Some((_, return_exp)) = &self.1 {
+            let value = return_exp.codegen(&mut block);
             block.add_return(Some(value))
         }
     }
+}
+
+impl Expression {
+    fn codegen(&self, block: &mut IRBlock) -> IRValue {
+        let Expression(kind, _) = self;
+
+        use ExpressionKind::*;
+        match kind {
+            Literal(lit) => IRValue::from_literal(lit, block),
+            _ => panic!("expression type not supported"),
+        }
+    }
+}