added the compiler

src/compiler.rs

@@ -0,0 +1,125 @@
+use std::collections::HashMap;
+use std::mem;
+use std::convert::TryInto;
+use inkwell::builder::Builder;
+use inkwell::context::Context;
+use inkwell::module::Module;
+use inkwell::values::{BasicValueEnum, FunctionValue, IntValue};
+
+use crate::ast;
+
+type Scope<'ctx> = HashMap<String, BasicValueEnum<'ctx>>;
+
+pub struct ModuleCodeGen<'ctx> {
+    context: &'ctx Context,
+    module: Module<'ctx>,
+    builder: Builder<'ctx>,
+    scope: Scope<'ctx>,
+}
+
+
+impl<'ctx> ModuleCodeGen<'ctx> {
+    pub fn new(context: &'ctx Context, name: String) -> Self {
+        return ModuleCodeGen{
+            context: context,
+            module: context.create_module(&name),
+            builder: context.create_builder(),
+            scope: Scope::new(),
+        }
+    }
+
+    pub fn gen_literal_int(&mut self, literal_int: ast::LiteralInt) -> IntValue<'ctx> {
+        self.context.i64_type().const_int(unsafe { mem::transmute::<i64, u64>(literal_int.value) }, true)
+    }
+
+    pub fn gen_op_expression(&mut self, scope: &Scope<'ctx>, lhs: Box<ast::Expression>, op: ast::Operator, rhs: Box<ast::Expression>) -> IntValue<'ctx> {
+        let lhs_result = self.gen_expression(scope, lhs);
+        let rhs_result = self.gen_expression(scope, rhs);
+        self.gen_op_int(lhs_result, rhs_result, op)
+    }
+
+    pub fn gen_op_int(&mut self, lhs: IntValue<'ctx>, rhs: IntValue<'ctx>, op: ast::Operator) -> IntValue<'ctx> {
+        match op {
+            ast::Operator::Plus => self.builder.build_int_add(lhs, rhs, "add"),
+            ast::Operator::Minus => self.builder.build_int_sub(lhs, rhs, "sub"),
+            ast::Operator::Mul => self.builder.build_int_mul(lhs, rhs, "mul"),
+            ast::Operator::Div => self.builder.build_int_signed_div(lhs, rhs, "div"),
+        }
+    }
+
+    pub fn gen_expression(&mut self, scope: &Scope<'ctx>, expression: Box<ast::Expression>) -> IntValue<'ctx> {
+        match *expression {
+            ast::Expression::LiteralInt(literal_int) => self.gen_literal_int(literal_int),
+            ast::Expression::Identifier(identifier) => {
+                match scope[&identifier.name] {
+                    BasicValueEnum::IntValue(value) => value,
+                    _ => panic!("function returned type other than int, no types yet"),
+                }
+            },
+            ast::Expression::FunctionCall(function_call) => self.gen_function_call(scope, function_call),
+            ast::Expression::Op(lhs, op, rhs) => self.gen_op_expression(scope, lhs, op, rhs),
+        }
+    }
+
+    pub fn gen_function_call(&mut self, scope: &Scope<'ctx>, function_call: ast::FunctionCall) -> IntValue<'ctx> {
+        println!("Calling function: {}", &function_call.name.name);
+        let fn_value = self.module.get_function(&function_call.name.name).unwrap();
+        let mut arguments = Vec::new();
+        for expression in function_call.arguments.into_iter() {
+            arguments.push(BasicValueEnum::IntValue(self.gen_expression(scope, expression)));
+        }
+
+        let result = self.builder.build_call(fn_value, &arguments, &function_call.name.name)
+            .try_as_basic_value()
+            .left()
+            .unwrap();
+        match result {
+            BasicValueEnum::IntValue(value) => value,
+            _ => panic!("function returned type other than int, no types yet"),
+        }
+    }
+
+    // Generates a FunctionValue for an `ast::Function`. This does not genereate a body,
+    // that task is left to the `gen_function` function. The reason this is split
+    // between two functions is that first all signatures are generated and then all bodies. This
+    // allows bodies to reference `FunctionValue` wherever they are declared in the file.
+    pub fn gen_signature(&mut self, function: &ast::Function) -> FunctionValue {
+        let mut args = Vec::new();
+        for _ in &function.arguments {
+            args.push(self.context.i64_type().into());
+        }
+        let fn_type = self.context.i64_type().fn_type(&args, false);
+        println!("Adding function: {}", &function.name.name);
+        let fn_value = self.module.add_function(&function.name.name, fn_type, None);
+        fn_value
+    }
+
+    pub fn gen_function(&mut self, function: ast::Function) {
+        let fn_value = self.module.get_function(&function.name.name).unwrap();
+        let basic_block = self.context.append_basic_block(fn_value, "entry");
+
+        self.builder.position_at_end(basic_block);
+
+        let mut scope = self.scope.clone();
+        for (i, param) in function.arguments.into_iter().enumerate() {
+            scope.insert(param.name.name, fn_value.get_nth_param(i.try_into().unwrap()).unwrap());
+        }
+        let body = function.block;
+        let return_value = self.gen_expression(&scope, body.expression);
+        self.builder.build_return(Some(&return_value));
+    }
+
+    pub fn gen_module(&mut self, module: ast::Module) {
+        // generate all signatures before the fuction bodies
+        for function in &module.functions {
+            self.gen_signature(&function);
+        }
+        for function in module.functions {
+            self.gen_function(function);
+        }
+    }
+
+    pub fn dump(&self) -> String {
+        self.module.print_to_string().to_string()
+    }
+}