From f51a8817aaae6bced7c12b1c6b14de74cc775595 Mon Sep 17 00:00:00 2001
From: Slendi <slendi@socopon.com>
Date: Thu, 8 Feb 2024 15:41:01 +0200
Subject: [PATCH] Create parser for if statements

---
 ast.odin    | 15 +++++++++++++++
 lexer.odin  |  1 +
 parser.odin | 42 +++++++++++++++++++++++++++++++++++++-----
 3 files changed, 53 insertions(+), 5 deletions(-)

diff --git a/ast.odin b/ast.odin
index 774b2ad..698303f 100644
--- a/ast.odin
+++ b/ast.odin
@@ -20,6 +20,8 @@ NodeKind :: enum {
 	Struct,
 	Enum,
 	Union,
+
+	If,
 }
 
 Node :: struct {
@@ -134,3 +136,16 @@ node_print :: proc(node: ^Node, indent := 0) {
 	}
 }
 
+node_create_if :: proc(range: TextRange, condition, then, else_: ^Node) -> (ret: ^Node) {
+	ret = new(Node)
+	ret^ = {
+		kind = .If,
+		range = range,
+		children = { condition, then },
+	}
+	if else_ != nil {
+		append(&ret.children, else_)
+	}
+	return
+}
+
diff --git a/lexer.odin b/lexer.odin
index 33658a8..ff8d1bf 100644
--- a/lexer.odin
+++ b/lexer.odin
@@ -259,6 +259,7 @@ lexer_read_identifier :: proc(lexer: ^Lexer) -> Token {
 	else if compare_dyn_arr_string(&str, "mut") { return token_create(.Mut, crange) }
 	else if compare_dyn_arr_string(&str, "as") { return token_create(.As, crange) }
 	else if compare_dyn_arr_string(&str, "in") { return token_create(.In, crange) }
+	else if compare_dyn_arr_string(&str, "if") { return token_create(.If, crange) }
 	else if compare_dyn_arr_string(&str, "else") { return token_create(.Else, crange) }
 	else if compare_dyn_arr_string(&str, "elif") { return token_create(.Elif, crange) }
 	else if compare_dyn_arr_string(&str, "for") { return token_create(.For, crange) }
diff --git a/parser.odin b/parser.odin
index b3309ec..68a5085 100644
--- a/parser.odin
+++ b/parser.odin
@@ -51,17 +51,49 @@ parser_parse_block :: proc(parser: ^Parser, end: TokenKind) -> (ret: ^Node) {
 	range := parser.tok.range
 	statements : [dynamic]^Node
 	for parser.tok.kind != end && parser.tok.kind != .EOF {
-		append(&statements, parser_parse_statement(parser))
+		stmt := parser_parse_statement(parser)
+		if stmt != nil {
+			append(&statements, stmt)
+		}
 	}
 	expect(parser, end)
 	return node_create_block(range, statements)
 }
 
 @(private = "file")
-parser_parse_statement :: proc(parser: ^Parser) -> ^Node {
-	ret := parser_parse_expression(parser)
-	expect(parser, .Semicolon)
-	return ret
+parser_parse_statement :: proc(parser: ^Parser) -> (ret: ^Node) {
+	if accept(parser, .Semicolon) {
+		ret = nil
+	} else if parser.tok.kind == .If {
+		range_beg := parser.tok.range
+		expect(parser, .If)
+		ret = parser_parse_if_statement(parser)
+		ret.range.start = range_beg.start
+	} else {
+		ret = parser_parse_expression(parser)
+		expect(parser, .Semicolon)
+	}
+	return
+}
+
+@(private = "file")
+parser_parse_if_statement :: proc(parser: ^Parser) -> ^Node {
+	range := parser.tok.range
+	expect(parser, .OpenParen)
+	condition := parser_parse_expression(parser)
+	expect(parser, .CloseParen)
+	expect(parser, .OpenBrace)
+	body := parser_parse_block(parser, .CloseBrace)
+	if accept(parser, .Elif) {
+		falsebody := parser_parse_if_statement(parser)
+		return node_create_if(range, condition, body, falsebody)
+	}
+	if accept(parser, .Else) {
+		expect(parser, .OpenBrace)
+		falsebody := parser_parse_block(parser, .CloseBrace)
+		return node_create_if(range, condition, body, falsebody)
+	}
+	return node_create_if(range, condition, body, nil)
 }
 
 @(private = "file")