From a693258d77ff7993b4b227853f97ff7af4b3644b Mon Sep 17 00:00:00 2001
From: augustin64 <me.git@augustin64.fr>
Date: Fri, 1 Dec 2023 14:27:48 +0100
Subject: [PATCH] Parser: Add while & for

---
 src/include/types.h |  4 +++
 src/parser.cpp      | 78 +++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 79 insertions(+), 3 deletions(-)

diff --git a/src/include/types.h b/src/include/types.h
index 8e4db0c..aa27909 100644
--- a/src/include/types.h
+++ b/src/include/types.h
@@ -36,6 +36,8 @@ Statement ->
     | { Prog }
     | If (Expr) Instruction
     | If (Expr) Instruction Else Instruction
+    | While (Expr) Instruction
+    | For (Expr | ExprStatement; Expr; Expr) Instruction
 
 ExprStatement -> 
     | Type ParIdentifier = Expr // AssignedDeclaration
@@ -114,6 +116,8 @@ enum class NodeType {
     RDecr, //                 -> ParIdentifier--
     If, //                    -> If (Expr) Instruction
     IfElse, //                -> If (Expr) Instruction Else Instruction
+    For, //                   -> For (Expr) Instruction
+    While, //                 -> While (Expr/ ExprStatement; Expr; Expr) Instruction
     Bloc, //                  -> { Prog }
     Lt, //                    -> Sum < Comp
     Gt, //                    -> Sum > Comp
diff --git a/src/parser.cpp b/src/parser.cpp
index 3e26f58..512f4dc 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -16,7 +16,7 @@ CodePosition null_pos = {
 const char* _node_names[] = {
     "Prog", "Epsilon", "AssignedDeclaration", "Declaration", "Plus", "Minus", "Mult", "Div", "Mod",
     "UnaryMinus", "UnaryPlus", "Neg", "Assignment", "LIncr", "RIncr", "LDecr", "RDecr", "If", "IfElse",
-    "Bloc", "Lt", "Gt", "Leq", "Geq", "Eq", "Neq", "Land", "Lor"
+    "For", "While", "Bloc", "Lt", "Gt", "Leq", "Geq", "Eq", "Neq", "Land", "Lor"
 };
 void _debug_print_tree(const Node& node, int depth, const string& prefix) {
     if (holds_alternative<InnerNode>(node)) {
@@ -168,13 +168,26 @@ ParseReturn parse_instruction(vector<Token> tokens) {
 }
 
 ParseReturn parse_statement(vector<Token> tokens) {
-    if (tokens.size() < 2) // 'If' / 'For' '(' at least
+    if (tokens.size() < 2)
         throw ParseException();
 
     switch (tokens.back().type) {
+        case TokenType::While:
         case TokenType::If: {
             CodePosition pos = tokens.back().pos;
 
+            NodeType type;
+            switch (tokens.back().type) {
+                case TokenType::If:
+                    type = NodeType::If;
+                    break;
+                case TokenType::While:
+                    type = NodeType::While;
+                    break;
+                default:
+                    break; // Impossible
+            }
+
             tokens.pop_back();
             if (tokens.back().type != TokenType::LParenthese) // Opening (
                 throw SyntaxError("Missing '('", tokens.back().pos);
@@ -215,7 +228,7 @@ ParseReturn parse_statement(vector<Token> tokens) {
 
             if (tokens.size() == 0 || tokens.back().type != TokenType::Else) { //* -> If (Expr) Instruction
                 InnerNode node = {
-                    .type=NodeType::If,
+                    .type=type,
                     .children={expr, instruction1},
                     .pos=pos
                 };
@@ -240,6 +253,65 @@ ParseReturn parse_statement(vector<Token> tokens) {
                 .tokens=tokens
             };
         }
+        case TokenType::For: {
+            CodePosition pos = tokens.back().pos;
+            tokens.pop_back();
+
+            if (tokens.back().type != TokenType::LParenthese) // Opening (
+                throw SyntaxError("Missing '('", tokens.back().pos);
+            tokens.pop_back();
+
+            ParseReturn ret1;
+            try {
+                ret1 = parse_expr_statement(tokens);
+            } catch (const ParseException& pex) {
+                ret1 = parse_expr(tokens);
+            }
+
+            int nb_tok = ret1.tokens.size(); // First ;
+            if (nb_tok == 0 || ret1.tokens.back().type != TokenType::Semicolon)
+                throw SyntaxError(
+                    "Expected ';'",
+                    nb_tok == 0 ? tokens.back().pos : ret1.tokens.back().pos
+                );
+            tokens = ret1.tokens;
+            tokens.pop_back();
+
+            ParseReturn ret2 = parse_expr(tokens);
+
+            nb_tok = ret2.tokens.size(); // Second ;
+            if (nb_tok == 0 || ret2.tokens.back().type != TokenType::Semicolon)
+                throw SyntaxError(
+                    "Expected ';'",
+                    nb_tok == 0 ? tokens.back().pos : ret2.tokens.back().pos
+                );
+            tokens = ret2.tokens;
+            tokens.pop_back();
+
+            ParseReturn ret3 = parse_expr(tokens);
+            
+            nb_tok = ret3.tokens.size(); // Closing )
+            if (nb_tok == 0 || ret3.tokens.back().type != TokenType::RParenthese)
+                throw SyntaxError(
+                    "Missing ')'",
+                    nb_tok == 0 ? tokens.back().pos : ret3.tokens.back().pos
+                );
+            tokens = ret3.tokens;
+            tokens.pop_back();
+
+            ParseReturn ret_instruction = parse_instruction(tokens);
+            tokens = ret_instruction.tokens;
+
+            InnerNode node = {
+                .type=NodeType::For,
+                .children={ret1.node, ret2.node, ret3.node, ret_instruction.node},
+                .pos=pos
+            };
+            return {
+                .node=node,
+                .tokens=tokens
+            };
+        }
         case TokenType::LCurlyBracket: {
             CodePosition pos = tokens.back().pos;
             tokens.pop_back();