From 88baba94a917221ffd6b4f15304ac560e7f2a6a8 Mon Sep 17 00:00:00 2001
From: Asami Doi <doiasami1219@gmail.com>
Date: Tue, 27 Aug 2019 14:14:15 +0900
Subject: [PATCH] Success running a fibonacci function!

---
 codegen.go |  5 +++++
 parse.go   | 43 ++++++++++++++++++++++++++++++++++++-------
 test.sh    |  3 +++
 3 files changed, 44 insertions(+), 7 deletions(-)

diff --git a/codegen.go b/codegen.go
index abfe63c..b142360 100644
--- a/codegen.go
+++ b/codegen.go
@@ -179,6 +179,11 @@ func codegen(prog Program) {
 		fmt.Printf("  mov rbp, rsp\n")
 		fmt.Printf("  sub rsp, %d\n", f.stackSize)
 
+		// Push parameters to the stack.
+		for i, p := range f.params {
+			fmt.Printf("  mov [rbp-%d], %s\n", p.offset, argreg[i])
+		}
+
 		// Emit code.
 		for _, s := range f.stmts {
 			gen(s)
diff --git a/parse.go b/parse.go
index 6e7751e..7993cf2 100644
--- a/parse.go
+++ b/parse.go
@@ -4,7 +4,7 @@ import (
 	"fmt"
 )
 
-var locals []Var
+var tmpLocals []Var
 var varOffset int = 8
 
 type Expr interface {
@@ -21,8 +21,9 @@ type Program struct {
 
 type Function struct {
 	name      string
-	stmts     []Stmt
+	params    []Var
 	locals    []Var
+	stmts     []Stmt
 	stackSize int
 }
 
@@ -90,7 +91,7 @@ func (For) isStmt()      {}
 func (Empty) isStmt()    {}
 
 func findVar(tok Token) *Var {
-	for _, v := range locals {
+	for _, v := range tmpLocals {
 		if v.name == tok.str {
 			return &v
 		}
@@ -138,8 +139,10 @@ func program() Program {
 func function() Function {
 	// Initialize for one function.
 	name := ""
+	params := make([]Var, 0)
+
 	varOffset = 8
-	locals = make([]Var, 0)
+	tmpLocals = make([]Var, 0)
 
 	if consume("func") {
 		tok := consumeIdent()
@@ -147,8 +150,10 @@ func function() Function {
 			panic("Expect an identifier after 'func' keyword.")
 		}
 		name = tok.str
-		// No sigunatures for now.
+		//fmt.Println("================")
+		//fmt.Println(tokens)
 		assert("(")
+		params = funcParams()
 		assert(")")
 	}
 
@@ -156,7 +161,7 @@ func function() Function {
 	for len(tokens) > 0 && !next("func") {
 		stmts = append(stmts, stmt())
 	}
-	return Function{name, stmts, locals, len(locals) * 8}
+	return Function{name, params, tmpLocals, stmts, len(tmpLocals) * 8}
 }
 
 func stmt() Stmt {
@@ -353,7 +358,7 @@ func primary() Expr {
 		if varp == nil {
 			varp = &Var{tok.str, varOffset}
 			varOffset += 8
-			locals = append(locals, *varp)
+			tmpLocals = append(tmpLocals, *varp)
 		}
 		return *varp
 	}
@@ -378,6 +383,30 @@ func funcArgs() []Expr {
 	return args
 }
 
+func funcParams() []Var {
+	params := make([]Var, 0)
+	if next(")") {
+		return params
+	}
+
+	for {
+		tok := consumeIdent()
+		if tok == nil {
+			panic("Expect an identifier inside function parameters.")
+		}
+
+		v := Var{tok.str, varOffset}
+		varOffset += 8
+		tmpLocals = append(tmpLocals, v)
+		params = append(params, v)
+
+		if !consume(",") {
+			break
+		}
+	}
+	return params
+}
+
 func printNodes(funcs []Function) {
 	for i, f := range funcs {
 		fmt.Println("[Function]:", i, f.name)
diff --git a/test.sh b/test.sh
index 20ca7be..be3d9a6 100755
--- a/test.sh
+++ b/test.sh
@@ -117,5 +117,8 @@ assert 2 'func main() { return sub(5, 3); }'
 assert 21 'func main() { return add6(1,2,3,4,5,6); }'
 
 assert 32 'func main() { return ret32(); } func ret32() { return 32; }'
+assert 7 'func main() { return add2(3,4); } func add2(x,y) { return x+y; }'
+assert 1 'func main() { return sub2(4,3); } func sub2(x,y) { return x-y; }'
+assert 55 'func main() { return fib(9); } func fib(x) { if x<=1 { return 1; } return fib(x-1) + fib(x-2); }'
 
 echo OK