add const keyword

Makefile

@@ -1,7 +1,7 @@
 
 MAKEFLAGS += -j16
 
-CXXFLAGS := -std=c++23 -Wall -Wextra -pedantic-errors -fsanitize=address,undefined
+CXXFLAGS := -std=c++23 -Wall -Wextra -pedantic-errors -fsanitize=address
 LDFLAGS := 
 
 CXXFLAGS += $(shell pkgconf sdl2 --cflags)

src/assembler.cpp

@@ -365,23 +365,6 @@ const auto reg_idents = std::unordered_map<std::string_view, vc5::Reg> {
     { "Rip", vc5::Reg::Rip },
 };
 
-char escape_char(char ch)
-{
-
-    switch (ch) {
-        case 'n':
-            return '\n';
-        case 'r':
-            return '\r';
-        case 't':
-            return '\t';
-        case '0':
-            return '\0';
-        default:
-            return ch;
-    }
-}
-
 }
 
 auto Parser::parse_operand() -> std::unique_ptr<Expr>
@@ -425,7 +408,8 @@ auto Parser::parse_operand() -> std::unique_ptr<Expr>
         auto text = std::string(m_tok.text);
         step();
 
-        int value = text.at(1) == '\\' ? escape_char(text.at(2)) : text.at(1);
+        int value = text.at(1) == '\\' ? unescape_escape_char(text.at(2))
+                                       : text.at(1);
 
         return std::make_unique<Expr>(
             loc, Expr::Ty::Int, static_cast<int>(value));
@@ -433,17 +417,7 @@ auto Parser::parse_operand() -> std::unique_ptr<Expr>
         auto text = std::string(m_tok.text);
         step();
 
-        auto value = std::string();
-        size_t i = 1;
-        while (i < text.size() - 1) {
-            if (text.at(i) == '\\') {
-                i += 1;
-                value.push_back(escape_char(text.at(i)));
-            } else {
-                value.push_back(text.at(i));
-            }
-            i += 1;
-        }
+        auto value = unescape_string(text.substr(1, text.size() - 2));
 
         return std::make_unique<Expr>(loc, Expr::Ty::Str, std::move(value));
     } else if (eat('(')) {

src/assembler.hpp

@@ -89,6 +89,18 @@ namespace asmer {
         Args args;
     };
 
+    struct Const {
+        Loc loc;
+        std::string_view ident;
+        std::unique_ptr<Expr> expr;
+    };
+
+    struct Align {
+        Loc loc;
+        std::string_view ident;
+        std::unique_ptr<Expr> expr;
+    };
+
     class Parser {
     public:
         explicit Parser(std::string_view text)

src/scanner.cpp

@@ -1,7 +1,9 @@
 #include "scanner.hpp"
+#include <cassert>
 #include <print>
 #include <string>
 #include <string_view>
+#include <unordered_map>
 
 using namespace vc5::tools;
 using namespace std::literals;
@@ -32,7 +34,18 @@ auto Scanner::next() -> Tok
             or test_range('a', 'z')) {
             step();
         }
-        return tok(TT::Ident, loc);
+
+        auto ident_tok = tok(TT::Ident, loc);
+
+        static const auto keywords = std::unordered_map<std::string_view, TT> {
+            { "const", TT::KwConst },
+        };
+
+        if (keywords.contains(ident_tok.text)) {
+            return tok(keywords.at(ident_tok.text), loc);
+        }
+
+        return ident_tok;
     }
     if (test_range('1', '9')) {
         while (test_range('0', '9')) {
@@ -232,3 +245,35 @@ void Loc::print_error(std::string_view text, std::string_view message) const
         message,
         clear);
 }
+
+auto vc5::tools::unescape_escape_char(char ch) -> char
+{
+    switch (ch) {
+        case 'n':
+            return '\n';
+        case 'r':
+            return '\r';
+        case 't':
+            return '\t';
+        case '0':
+            return '\0';
+        default:
+            return ch;
+    }
+}
+
+auto vc5::tools::unescape_string(std::string_view value) -> std::string
+{
+    auto result = std::string();
+    size_t i = 0;
+    while (i < value.size()) {
+        if (value[0] == '\\') {
+            i += 1;
+            result += unescape_escape_char(value[i]);
+        } else {
+            result += value[i];
+        }
+        i += 1;
+    }
+    return result;
+}

src/scanner.hpp

@@ -22,6 +22,7 @@ struct Tok {
         Bin,
         Char,
         Str,
+        KwConst,
         Newline = '\n',
         LParen = '(',
         RParen = ')',
@@ -76,4 +77,7 @@ private:
     bool m_error_occured = false;
 };
 
+auto unescape_escape_char(char ch) -> char;
+auto unescape_string(std::string_view value) -> std::string;
+
 }