Make string and char pointers comparable

config-lang.in

@@ -1,3 +1,20 @@
+# config-lang.in -- Top level configure fragment for gcc Elna frontend.
+# Copyright (C) 2025 Free Software Foundation, Inc.
+
+# GCC is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+
+# GCC is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with GCC; see the file COPYING3.  If not see
+# <http://www.gnu.org/licenses/>.
+
 language="elna"
 gcc_subdir="elna/gcc"
 

gcc/Make-lang.in

@@ -1,3 +1,20 @@
+# Make-lang.in -- Top level -*- makefile -*- fragment for the Elna frontend.
+# Copyright (C) 2025 Free Software Foundation, Inc.
+
+# GCC is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+
+# GCC is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with GCC; see the file COPYING3.  If not see
+# <http://www.gnu.org/licenses/>.
+
 ELNA_INSTALL_NAME := $(shell echo gelna|sed '$(program_transform_name)')
 ELNA_TARGET_INSTALL_NAME := $(target_noncanonical)-$(shell echo gelna|sed '$(program_transform_name)')
 

gcc/config-lang.in

@@ -1,3 +1,27 @@
+# config-lang.in -- Top level configure fragment for gcc Elna frontend.
+# Copyright (C) 2025 Free Software Foundation, Inc.
+
+# GCC is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+
+# GCC is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with GCC; see the file COPYING3.  If not see
+# <http://www.gnu.org/licenses/>.
+
+# Configure looks for the existence of this file to auto-config each language.
+# We define several parameters used by configure:
+#
+# language	- name of language as it would appear in $(LANGUAGES)
+# boot_language	- "yes" if we need to build this language in stage1
+# compilers	- value to add to $(COMPILERS)
+
 language="elna"
 gcc_subdir="elna/gcc"
 

gcc/elna-convert.cc

@@ -1,3 +1,20 @@
+/* elna-convert.cc -- Data type conversion routines.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
 #include "config.h"
 #include "system.h"
 #include "coretypes.h"

gcc/elna-diagnostic.cc

@@ -1,3 +1,20 @@
+/* elna-diagnostic.cc -- Elna frontend specific diagnostic routines.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
 #include "elna/gcc/elna-diagnostic.h"
 #include "elna/gcc/elna-tree.h"
 
@@ -12,7 +29,7 @@ namespace gcc
         return linemap_position_for_column(line_table, position->column);
     }
 
-    const char *print_type(tree type)
+    std::string print_type(tree type)
     {
         gcc_assert(TYPE_P(type));
 
@@ -38,7 +55,7 @@ namespace gcc
         }
         else if (is_pointer_type(type))
         {
-            return "pointer";
+            return std::string("\"pointer to " + print_type(TREE_TYPE(type)) + "\"");
         }
         else if (TREE_CODE(type) == ARRAY_TYPE)
         {

gcc/elna-generic.cc

@@ -1,3 +1,20 @@
+/* elna-generic.cc -- Visitor generating a GENERIC tree.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
 #include <array>
 
 #include "elna/gcc/elna-generic.h"
@@ -295,6 +312,7 @@ namespace gcc
         tree index_constant = build_int_cstu(index_type, string->number().size());
         tree element_type = this->symbol_map->lookup("Char");
         tree string_type = build_array_type(element_type, build_index_type(index_constant));
+        tree string_record = this->symbol_map->lookup("String");
 
         tree string_literal = build_string(string->number().size(), string->number().c_str());
         TREE_TYPE(string_literal) = string_type;
@@ -302,12 +320,11 @@ namespace gcc
         TREE_READONLY(string_literal) = 1;
         TREE_STATIC(string_literal) = 1;
 
-        string_type = build_pointer_type(element_type);
+        string_type = TREE_TYPE(TREE_CHAIN(TYPE_FIELDS(string_record)));
         string_literal = build4(ARRAY_REF, element_type, string_literal, integer_zero_node, NULL_TREE, NULL_TREE);
         string_literal = build1(ADDR_EXPR, string_type, string_literal);
 
         vec<constructor_elt, va_gc> *elms = NULL;
-        tree string_record = this->symbol_map->lookup("String");
         CONSTRUCTOR_APPEND_ELT(elms, TYPE_FIELDS(string_record), index_constant);
         CONSTRUCTOR_APPEND_ELT(elms, TREE_CHAIN(TYPE_FIELDS(string_record)), string_literal);
 
@@ -373,11 +390,11 @@ namespace gcc
             }
             return;
         }
-        if (left_type != right_type && !are_compatible_pointers(left, right))
+        if (left_type != right_type && !are_compatible_pointers(left, right) && !are_compatible_pointers(right, left))
         {
             error_at(expression_location,
                     "invalid operands of type %s and %s for operator %s",
-                    print_type(left_type), print_type(right_type),
+                    print_type(left_type).c_str(), print_type(right_type).c_str(),
                     boot::print_binary_operator(expression->operation()));
             this->current_expression = error_mark_node;
             return;
@@ -719,7 +736,7 @@ namespace gcc
             return;
         }
         if (TREE_TYPE(this->current_expression) == TREE_TYPE(lvalue)
-                || (is_pointer_type(TREE_TYPE(lvalue)) && this->current_expression == null_pointer_node))
+                || are_compatible_pointers(lvalue, this->current_expression))
         {
             tree assignment = build2_loc(statement_location, MODIFY_EXPR,
                     void_type_node, lvalue, this->current_expression);
@@ -731,8 +748,8 @@ namespace gcc
         {
             error_at(statement_location,
                     "cannot assign value of type %s to variable of type %s",
-                    print_type(TREE_TYPE(this->current_expression)),
+                    print_type(TREE_TYPE(this->current_expression)).c_str(),
-                    print_type(TREE_TYPE(lvalue)));
+                    print_type(TREE_TYPE(lvalue)).c_str());
             this->current_expression = error_mark_node;
         }
     }
@@ -771,7 +788,7 @@ namespace gcc
         {
             error_at(get_location(&branch.prerequisite().position()),
                     "expected expression of boolean type but its type is %s",
-                    print_type(TREE_TYPE(this->current_expression)));
+                    print_type(TREE_TYPE(this->current_expression)).c_str());
             this->current_expression = error_mark_node;
             return;
         }
@@ -818,7 +835,7 @@ namespace gcc
         {
             error_at(get_location(&statement->body().prerequisite().position()),
                     "expected expression of boolean type but its type is %s",
-                    print_type(TREE_TYPE(this->current_expression)));
+                    print_type(TREE_TYPE(this->current_expression)).c_str());
             this->current_expression = error_mark_node;
             return;
         }

gcc/elna-spec.cc

@@ -1,3 +1,20 @@
+/* elna-spec.c -- Specific flags and argument handling of the Elna front end.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
 void
 lang_specific_driver (struct cl_decoded_option ** /* in_decoded_options */,
 		      unsigned int * /* in_decoded_options_count */,

gcc/elna-tree.cc

@@ -1,3 +1,20 @@
+/* elna-tree.cc -- Utilities to manipulate GCC trees.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
 #include "elna/gcc/elna-tree.h"
 #include "elna/gcc/elna-diagnostic.h"
 
@@ -24,8 +41,11 @@ namespace gcc
 
     bool are_compatible_pointers(tree lhs, tree rhs)
     {
-        return (lhs == null_pointer_node || rhs == null_pointer_node)
+        tree lhs_type = TREE_TYPE(lhs);
-            && is_pointer_type(TREE_TYPE(lhs)) && is_pointer_type(TREE_TYPE(rhs));
+        tree rhs_type = TREE_TYPE(rhs);
+
+        return (is_pointer_type(lhs_type) && rhs == null_pointer_node)
+            || (is_pointer_type(lhs_type) && lhs_type == rhs_type);
     }
 
     tree tree_chain_base::head()
@@ -141,7 +161,7 @@ namespace gcc
 
         record_chain.append(build_field(UNKNOWN_LOCATION, string_record, "length", initial_table->lookup("Word")));
         record_chain.append(build_field(UNKNOWN_LOCATION, string_record, "ptr",
-                    build_pointer_type(initial_table->lookup("Char"))));
+                    build_pointer_type_for_mode(initial_table->lookup("Char"), VOIDmode, true)));
 
         TYPE_FIELDS(string_record) = record_chain.head();
         layout_type(string_record);
@@ -216,7 +236,7 @@ namespace gcc
         {
             error_at(expression_location,
                     "invalid operands of type %s and %s for operator %s",
-                    print_type(left_type), print_type(right_type),
+                    print_type(left_type).c_str(), print_type(right_type).c_str(),
                     elna::boot::print_binary_operator(expression->operation()));
             return error_mark_node;
         }

gcc/elna1.cc

@@ -1,3 +1,20 @@
+/* elna1.cc -- Language-dependent hooks for Elna.
+   Copyright (C) 2006-2024 Free Software Foundation, Inc.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
 #include "config.h"
 #include "system.h"
 #include "coretypes.h"

gcc/lang-specs.h

@@ -1,3 +1,20 @@
+/* lang-specs.h -- GCC driver specs for Elna frontend.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
 /* gcc/gcc.cc */
 {".elna",  "@elna", nullptr, 0, 0},
 {"@elna",

include/elna/boot/ast.h

@@ -648,11 +648,11 @@ namespace boot
     template<typename T>
     class number_literal : public literal
     {
-        T m_number;
+        T m_value;
 
     public:
-        number_literal(const struct position position, const T value)
+        number_literal(const struct position position, const T& value)
-            : literal(position), m_number(value)
+            : literal(position), m_value(value)
         {
         }
 
@@ -663,7 +663,7 @@ namespace boot
 
         const T& number() const
         {
-            return m_number;
+            return m_value;
         }
     };
 

include/elna/gcc/elna-diagnostic.h

@@ -1,3 +1,20 @@
+/* elna-diagnostic.h -- Elna frontend specific diagnostic routines.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
 #pragma once
 
 #include "config.h"
@@ -14,6 +31,6 @@ namespace gcc
 {
     location_t get_location(const boot::position *position);
 
-    const char *print_type(tree type);
+    std::string print_type(tree type);
 }
 }

include/elna/gcc/elna-generic.h

@@ -1,3 +1,20 @@
+/* elna-generic.h -- Visitor generating a GENERIC tree.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
 #pragma once
 
 #include "elna/boot/ast.h"

include/elna/gcc/elna-tree.h

@@ -1,3 +1,20 @@
+/* elna-tree.h -- Utilities to manipulate GCC trees.
+   Copyright (C) 2025 Free Software Foundation, Inc.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
 #pragma once
 
 #include <forward_list>
@@ -17,6 +34,12 @@ namespace gcc
 {
     bool is_pointer_type(tree type);
     bool is_integral_type(tree type);
+
+    /**
+     * \param lhs Left hand value.
+     * \param rhs Right hand value.
+     * \return Whether rhs can be assigned to lhs.
+     */
     bool are_compatible_pointers(tree lhs, tree rhs);
 
     class tree_chain_base

source.elna

@@ -25,9 +25,14 @@ type
     first: Position;
 	last: Position
   end,
+  SourceCode = record
+    position: Position;
+	text: String
+  end,
   TokenValue* = union
     int_value: Int;
     string_value: pointer to Char;
+    string: String;
 	boolean_value: Bool;
 	char_value: Char
   end,
@@ -179,11 +184,32 @@ begin
   return strncmp(this.ptr, that, length) = 0
 end
 
+proc open_substring(string: String, start: Word): String;
+begin
+  string.ptr := string.ptr + start;
+  string.length := string.length - start;
+  return string
+end
+
+proc char_at(string: String, position: Word): Char;
+begin
+  return (string.ptr + position)^
+end
+
 (*
   End of standard procedures.
 *)
 
-proc read_source(filename: pointer to Char): pointer to Char;
+proc make_position(): Position;
+var
+  result: Position;
+begin
+  result.line := 1u;
+  result.column := 1u;
+  return result
+end
+
+proc read_source(filename: pointer to Char, result: pointer to String): Bool;
 var
   input_file: pointer to FILE,
   source_size: Int,
@@ -192,26 +218,28 @@ begin
   input_file := fopen(filename, "rb\0".ptr);
 
   if input_file = nil then
-    return nil
+    return false
+  end;
+  defer
+    fclose(input_file)
   end;
   if fseek(input_file, 0, SEEK_END) <> 0 then
-    fclose(input_file);
+    return false
-    return nil
   end;
   source_size := ftell(input_file);
   if source_size < 0 then
-    fclose(input_file);
+    return false
-    return nil
   end;
   rewind(input_file);
 
-  input := calloc(source_size + 1, 1);
+  input := malloc(source_size);
   if fread(input, source_size, 1, input_file) <> 1u then
-    input := nil
+    return false
   end;
-  fclose(input_file);
+  result^.length := cast(source_size as Word);
+  result^.ptr := cast(input as pointer to Char);
 
-  return input
+  return true
 end
 
 proc escape_char(escape: Char, result: pointer to Char): Bool;
@@ -257,12 +285,26 @@ begin
   end
 end
 
-proc skip_spaces(input: pointer to Char): pointer to Char;
+proc advance_source(source_code: SourceCode, length: Word): SourceCode;
 begin
-  while is_space(input^) do
+  source_code.text := open_substring(source_code.text, length);
-    input := input + 1
+  source_code.position.column := source_code.position.column + length;
+
+  return source_code
+end
+
+proc skip_spaces(source_code: SourceCode): SourceCode;
+begin
+  while source_code.text.length > 0u and is_space(char_at(source_code.text, 0)) do
+    if char_at(source_code.text, 0) = '\n' then
+      source_code.position.line := source_code.position.line + 1u;
+      source_code.position.column := 1u
+	else
+	  source_code.position.column := source_code.position.column + 1u
 	end;
-  return input
+    source_code.text := open_substring(source_code.text, 1u)
+  end;
+  return source_code
 end
 
 proc lex_identifier(input: pointer to Char): pointer to Char;
@@ -273,19 +315,29 @@ begin
   return input
 end
 
-proc lex_comment(input: pointer to Char): pointer to Char;
+proc lex_comment(source_code: pointer to SourceCode, token_content: pointer to String): Bool;
 var
-  next: pointer to Char;
+  result: pointer to Char;
 begin
-  while input^ <> '\0' do
+  token_content^.ptr := source_code^.text.ptr;
-    next := input + 1;
+  token_content^.length := 0u;
 
-    if input^ = '*' and next^ = ')' then
+  while source_code^.text.length > 1u do
-	  return next + 1
+    if char_at(source_code^.text, 0) = '*' and char_at(source_code^.text, 1) = ')' then
+	  source_code^ := advance_source(source_code^, 2u);
+
+	  result := cast(malloc(token_content^.length) as pointer to Char);
+	  strncpy(result, token_content^.ptr, token_content^.length);
+	  token_content^.ptr := result;
+
+	  return true
 	end;
-	input := next
+	token_content^.length := token_content^.length + 1u;
+	source_code^ := advance_source(source_code^, 1)
   end;
-  return nil
+  token_content^.ptr := nil;
+  token_content^.length := 0u;
+  return false
 end
 
 proc lex_character(input: pointer to Char, current_token: pointer to Token): pointer to Char;
@@ -458,7 +510,7 @@ begin
 	elsif current_token^.kind = TOKEN_AT then
 	  write_c('@')
 	elsif current_token^.kind = TOKEN_COMMENT then
-	  write_s("COMMENT")
+	  write_s("(* COMMENT *)")
 	elsif current_token^.kind = TOKEN_INTEGER then
 	  write_c('<');
       write_i(current_token^.value.int_value);
@@ -562,154 +614,167 @@ begin
   return current_token
 end
 
-proc tokenize(input_pointer: pointer to Char, tokens_size: pointer to Word): pointer to Token;
+proc tokenize(source_code: SourceCode, tokens_size: pointer to Word): pointer to Token;
 var
   token_end: pointer to Char,
   tokens: pointer to Token,
   current_token: pointer to Token,
-  token_length: Word;
+  token_length: Word,
+  first_char: Char,
+  token_content: String;
 begin
   tokens_size^ := 0u;
   tokens := nil;
+  source_code := skip_spaces(source_code);
 
-  input_pointer := skip_spaces(input_pointer);
+  while source_code.text.length <> 0u do
-
-  while input_pointer^ <> '\0' do
 	tokens := cast(reallocarray(tokens, tokens_size^ + 1u, sizeof(Token)) as pointer to Token);
     current_token := tokens + tokens_size^;
+	first_char := char_at(source_code.text, 0);
 
-    if is_alpha(input_pointer^) or input_pointer^ = '_' then
+    if is_alpha(first_char) or first_char = '_' then
-      token_end := lex_identifier(input_pointer + 1);
+      token_end := lex_identifier(source_code.text.ptr + 1);
-	  token_length := cast(token_end as Word) - cast(input_pointer as Word);
+	  token_length := cast(token_end - source_code.text.ptr as Word);
 
-      current_token^ := categorize_identifier(input_pointer, token_length);
+      current_token^ := categorize_identifier(source_code.text.ptr, token_length);
 
-	  input_pointer := token_end
+      source_code := advance_source(source_code, token_length)
-	elsif is_digit(input_pointer^) then
+	elsif is_digit(first_char) then
 	  token_end := nil;
-	  current_token^.value.int_value := strtol(input_pointer, @token_end, 10);
+	  current_token^.value.int_value := strtol(source_code.text.ptr, @token_end, 10);
+	  token_length := cast(token_end - source_code.text.ptr as Word);
 
 	  if token_end^ = 'u' then
 	    current_token^.kind := TOKEN_WORD;
-	    input_pointer := token_end + 1
+        source_code := advance_source(source_code, token_length + 1u)
 	  else
 	    current_token^.kind := TOKEN_INTEGER;
-	    input_pointer := token_end
+        source_code := advance_source(source_code, token_length)
 	  end
-	elsif input_pointer^ = '(' then
+	elsif first_char = '(' then
-      input_pointer := input_pointer + 1;
+	  source_code := advance_source(source_code, 1u);
-	  if input_pointer^ = '*' then
-	    token_end := lex_comment(input_pointer + 1);
 
-		if token_end <> nil then
+	  if source_code.text.length = 0u then
-	      token_length := cast(token_end as Word) - cast(input_pointer as Word);
+	    current_token^.kind := TOKEN_LEFT_PAREN
-	      current_token^.value.string_value := cast(calloc(token_length + 1u, 1) as pointer to Char);
+	  elsif char_at(source_code.text, 0u) = '*' then
-	      strncpy(current_token^.value.string_value, input_pointer, token_length);
+	    source_code := advance_source(source_code, 1u);
-		  current_token^.kind := TOKEN_COMMENT;
 
-		  input_pointer := token_end
+		if lex_comment(@source_code, @token_content) then
+	      current_token^.value.string := token_content;
+		  current_token^.kind := TOKEN_COMMENT
 		else
 	      current_token^.kind := 0
 		end
 	  else
 	    current_token^.kind := TOKEN_LEFT_PAREN
 	  end
-	elsif input_pointer^ = ')' then
+	elsif first_char = ')' then
 	  current_token^.kind := TOKEN_RIGHT_PAREN;
-      input_pointer := input_pointer + 1
+	  source_code := advance_source(source_code, 1u)
-	elsif input_pointer^ = '\'' then
+	elsif first_char = '\'' then
-	  token_end := lex_character(input_pointer + 1, current_token);
+	  token_end := lex_character(source_code.text.ptr + 1, current_token);
+	  token_length := cast(token_end - source_code.text.ptr as Word);
 
 	  if token_end^ = '\'' then
 	  	current_token^.kind := TOKEN_CHARACTER;
-	    input_pointer := token_end + 1
+	    source_code := advance_source(source_code, token_length + 1u)
 	  else
-	    input_pointer := input_pointer + 1
+	    source_code := advance_source(source_code, 1u)
 	  end
-	elsif input_pointer^ = '"' then
+	elsif first_char = '"' then
-	  token_end := lex_string(input_pointer + 1, current_token);
+	  token_end := lex_string(source_code.text.ptr + 1, current_token);
 
       if token_end^ = '"' then
 		current_token^.kind := TOKEN_STRING;
-	    input_pointer := token_end + 1
+	    token_length := cast(token_end - source_code.text.ptr as Word);
+	    source_code := advance_source(source_code, token_length + 1u)
 	  end
-	elsif input_pointer^ = '[' then
+	elsif first_char = '[' then
 	  current_token^.kind := TOKEN_LEFT_SQUARE;
-      input_pointer := input_pointer + 1
+	  source_code := advance_source(source_code, 1u)
-	elsif input_pointer^ = ']' then
+	elsif first_char = ']' then
 	  current_token^.kind := TOKEN_RIGHT_SQUARE;
-      input_pointer := input_pointer + 1
+	  source_code := advance_source(source_code, 1u)
-	elsif input_pointer^ = '>' then
+	elsif first_char = '>' then
-	  input_pointer := input_pointer + 1;
+	  source_code := advance_source(source_code, 1u);
-	  if input_pointer^ = '=' then
+
+      if source_code.text.length = 0u then
+	    current_token^.kind := TOKEN_GREATER_THAN
+	  elsif char_at(source_code.text, 0) = '=' then
 	    current_token^.kind := TOKEN_GREATER_EQUAL;
-		input_pointer := input_pointer + 1
+	    source_code := advance_source(source_code, 1u)
 	  else
 	    current_token^.kind := TOKEN_GREATER_THAN
 	  end
-	elsif input_pointer^ = '<' then
+	elsif first_char = '<' then
-	  input_pointer := input_pointer + 1;
+	  source_code := advance_source(source_code, 1u);
-	  if input_pointer^ = '=' then
+
+	  if source_code.text.length = 0u then
+	    current_token^.kind := TOKEN_LESS_THAN
+	  elsif char_at(source_code.text, 0) = '=' then
 	    current_token^.kind := TOKEN_LESS_EQUAL;
-		input_pointer := input_pointer + 1
+	    source_code := advance_source(source_code, 1u)
-	  elsif input_pointer^ = '>' then
+	  elsif char_at(source_code.text, 0) = '>' then
 	    current_token^.kind := TOKEN_NOT_EQUAL;
-		input_pointer := input_pointer + 1
+	    source_code := advance_source(source_code, 1u)
 	  else
 	    current_token^.kind := TOKEN_LESS_THAN
 	  end
-	elsif input_pointer^ = '=' then
+	elsif first_char = '=' then
 	  current_token^.kind := TOKEN_EQUAL;
-	  input_pointer := input_pointer + 1
+	  source_code := advance_source(source_code, 1u)
-	elsif input_pointer^ = ';' then
+	elsif first_char = ';' then
 	  current_token^.kind := TOKEN_SEMICOLON;
-	  input_pointer := input_pointer + 1
+	  source_code := advance_source(source_code, 1u)
-	elsif input_pointer^ = '.' then
+	elsif first_char = '.' then
 	  current_token^.kind := TOKEN_DOT;
-	  input_pointer := input_pointer + 1
+	  source_code := advance_source(source_code, 1u)
-	elsif input_pointer^ = ',' then
+	elsif first_char = ',' then
 	  current_token^.kind := TOKEN_COMMA;
-	  input_pointer := input_pointer + 1
+	  source_code := advance_source(source_code, 1u)
-	elsif input_pointer^ = '+' then
+	elsif first_char = '+' then
 	  current_token^.kind := TOKEN_PLUS;
-	  input_pointer := input_pointer + 1
+	  source_code := advance_source(source_code, 1u)
-	elsif input_pointer^ = '-' then
+	elsif first_char = '-' then
 	  current_token^.kind := TOKEN_MINUS;
-	  input_pointer := input_pointer + 1
+	  source_code := advance_source(source_code, 1u)
-	elsif input_pointer^ = '*' then
+	elsif first_char = '*' then
 	  current_token^.kind := TOKEN_MULTIPLICATION;
-	  input_pointer := input_pointer + 1
+	  source_code := advance_source(source_code, 1u)
-	elsif input_pointer^ = '/' then
+	elsif first_char = '/' then
 	  current_token^.kind := TOKEN_DIVISION;
-	  input_pointer := input_pointer + 1
+	  source_code := advance_source(source_code, 1u)
-	elsif input_pointer^ = '%' then
+	elsif first_char = '%' then
 	  current_token^.kind := TOKEN_REMAINDER;
-	  input_pointer := input_pointer + 1
+	  source_code := advance_source(source_code, 1u)
-	elsif input_pointer^ = ':' then
+	elsif first_char = ':' then
-	  input_pointer := input_pointer + 1;
+	  source_code := advance_source(source_code, 1u);
-	  if input_pointer^ = '=' then
+
+	  if source_code.text.length = 0u then
+	    current_token^.kind := TOKEN_COLON
+	  elsif char_at(source_code.text, 0) = '=' then
 	    current_token^.kind := TOKEN_ASSIGNMENT;
-	    input_pointer := input_pointer + 1
+	    source_code := advance_source(source_code, 1u)
 	  else
 	    current_token^.kind := TOKEN_COLON
 	  end
-	elsif input_pointer^ = '^' then
+	elsif first_char = '^' then
 	  current_token^.kind := TOKEN_HAT;
-	  input_pointer := input_pointer + 1
+	  source_code := advance_source(source_code, 1u)
-	elsif input_pointer^ = '@' then
+	elsif first_char = '@' then
 	  current_token^.kind := TOKEN_AT;
-	  input_pointer := input_pointer + 1
+	  source_code := advance_source(source_code, 1u)
 	else
 	  current_token^.kind := 0;
-      input_pointer := input_pointer + 1
+	  source_code := advance_source(source_code, 1u)
 	end;
 
 	if current_token^.kind <> 0 then
       tokens_size^ := tokens_size^ + 1u;
-      input_pointer := skip_spaces(input_pointer)
+      source_code := skip_spaces(source_code)
 	else
 	  write_s("Lexical analysis error on \"");
-	  write_c(input_pointer^);
+	  write_c(first_char);
 	  write_s("\".\n")
 	end
   end;
@@ -819,9 +884,9 @@ end
 
 proc process(argc: Int, argv: pointer to pointer to Char): Int;
 var
-  input: pointer to Char,
   tokens: pointer to Token,
   tokens_size: Word,
+  source_code: SourceCode,
   command_line: pointer to CommandLine;
 begin
   command_line := parse_command_line(argc, argv);
@@ -829,12 +894,12 @@ begin
     return 2
   end;
 
-  input := read_source(command_line^.input);
+  source_code.position := make_position();
-  if input = nil then
+  if not read_source(command_line^.input, @source_code.text) then
     perror(command_line^.input);
 	return 3
   end;
-  tokens := tokenize(input, @tokens_size);
+  tokens := tokenize(source_code, @tokens_size);
 
   if command_line^.tokenize then
     print_tokens(tokens, tokens_size)