From f8ed70336d6288f6102d23865d62653863056bfc Mon Sep 17 00:00:00 2001
From: MrLetsplay <mr@cringe-studios.com>
Date: Tue, 12 Mar 2024 22:00:03 +0100
Subject: [PATCH] More function parsing

---
 example/helloworld.lang |  2 +-
 parser.go               | 81 +++++++++++++++++++++++++++++++++++++++--
 2 files changed, 78 insertions(+), 5 deletions(-)

diff --git a/example/helloworld.lang b/example/helloworld.lang
index 34cbb87..97a886f 100644
--- a/example/helloworld.lang
+++ b/example/helloworld.lang
@@ -1,7 +1,7 @@
 import lang.stdlib;
 
 (u8, u8) a(u8 a, u8 b) {
-	return a, b
+	return a, b;
 }
 
 void main() {
diff --git a/parser.go b/parser.go
index 2a8c01b..c547689 100644
--- a/parser.go
+++ b/parser.go
@@ -108,8 +108,14 @@ type Block struct {
 	Statements []Statement
 }
 
+type ParsedParameter struct {
+	Name string
+	Type Type
+}
+
 type ParsedFunction struct {
-	Parameters []Type
+	Name       string
+	Parameters []ParsedParameter
 	ReturnType Type
 	Body       Block
 }
@@ -141,6 +147,19 @@ func expectSeparator(tokens []LexToken, separators ...Separator) (Separator, []L
 	return separator.Value.(Separator), tokens[1:], nil
 }
 
+func expectIdentifier(tokens []LexToken) (string, []LexToken, error) {
+	if len(tokens) == 0 {
+		return "", nil, errors.New("expected identifier")
+	}
+
+	token := tokens[0]
+	if token.Type != Type_Separator && token.Type != Type_Identifier {
+		return "", nil, errors.New("expected identifier")
+	}
+
+	return token.Value.(string), tokens[1:], nil
+}
+
 func parseImport(tokens []LexToken) (*Import, []LexToken, error) {
 	var err error
 
@@ -216,7 +235,8 @@ func parseType(tokens []LexToken) (*Type, []LexToken, error) {
 func parseFunction(tokens []LexToken) (*ParsedFunction, []LexToken, error) {
 	var err error
 
-	var parameters []Type
+	var name string
+	var parameters []ParsedParameter
 	var returnType *Type
 	var body Block
 
@@ -225,9 +245,62 @@ func parseFunction(tokens []LexToken) (*ParsedFunction, []LexToken, error) {
 		return nil, nil, err
 	}
 
-	// TODO: function name, parameters, body
+	if len(tokens) < 2 {
+		return nil, nil, errors.New("incomplete function declaration")
+	}
 
-	return &ParsedFunction{Parameters: parameters, ReturnType: *returnType, Body: body}, tokens, nil
+	name, tokens, err = expectIdentifier(tokens)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	_, tokens, err = expectSeparator(tokens, Separator_OpenParen)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	for {
+		if len(tokens) == 0 {
+			return nil, nil, errors.New("incomplete function declaration")
+		}
+
+		token := tokens[0]
+		if token.Type == Type_Separator && token.Value.(Separator) == Separator_CloseParen {
+			tokens = tokens[1:]
+			break
+		}
+
+		if len(parameters) > 0 {
+			if token.Type != Type_Separator && token.Value.(Separator) != Separator_Comma {
+				return nil, nil, errors.New("expected ,")
+			}
+
+			tokens = tokens[1:]
+		}
+
+		var paramType *Type
+		paramType, tokens, err = parseType(tokens)
+		if err != nil {
+			return nil, nil, err
+		}
+
+		var paramName string
+		paramName, tokens, err = expectIdentifier(tokens)
+		if err != nil {
+			return nil, nil, err
+		}
+
+		parameters = append(parameters, ParsedParameter{Name: paramName, Type: *paramType})
+	}
+
+	_, tokens, err = expectSeparator(tokens, Separator_OpenCurly)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// TODO: body, closing curly
+
+	return &ParsedFunction{Name: name, Parameters: parameters, ReturnType: *returnType, Body: body}, tokens, nil
 }
 
 func parser(tokens []LexToken) (*ParsedFile, error) {