Merge pull request #28 from LangProc/dev

Added better error messages in Flex with yylineno + some minor visual fixes

Author: Fiwo735

Makefile

@@ -18,9 +18,9 @@ DEPENDENCIES := $(patsubst src/%.cpp,build/%.d,$(SOURCES))
 OBJECTS := $(patsubst src/%.cpp,build/%.o,$(SOURCES))
 OBJECTS += build/parser.tab.o build/lexer.yy.o
 
-.PHONY: default clean coverage
+.PHONY: default clean coverage remove_old_gcda
 
-default: bin/c_compiler
+default: remove_old_gcda bin/c_compiler
 
 bin/c_compiler: $(OBJECTS)
 	@mkdir -p bin
@@ -47,6 +47,9 @@ coverage:
 	genhtml coverage/cov.info -o coverage
 	@find . -name "*.gcda" -delete
 
+remove_old_gcda:
+	@find . -name "*.gcda" -delete
+
 clean :
 	@rm -rf coverage/
 	@rm -rf build/

src/compiler.cpp

@@ -42,7 +42,7 @@ int main(int argc, char **argv)
 
 NodePtr Parse(const std::string& compile_source_path)
 {
-    std::cout << "Parsing ..." << compile_source_path << std::endl;
+    std::cout << "Parsing " << compile_source_path << "..." << std::endl;
 
     NodePtr root = ParseAST(compile_source_path);
 

src/lexer.flex

@@ -1,15 +1,17 @@
 %option noyywrap
+%option yylineno
 
 %{
   // A lot of this lexer is based off the ANSI C grammar:
-  // https://www.lysator.liu.se/c/ANSI-C-grammar-l.html#MUL-ASSIGN
-  // Avoid error "error: `fileno' was not declared in this scope"
+  // https://www.lysator.liu.se/c/ANSI-C-grammar-l.html
+
+  // Avoids error "error: `fileno' was not declared in this scope"
   extern "C" int fileno(FILE *stream);
 
   #include "parser.tab.hpp"
 
   // Suppress warning about unused function
-  [[maybe_unused]] static void yyunput (int c, char * yy_bp );
+  [[maybe_unused]] static void yyunput (int c, char * yy_bp);
 %}
 
 D	  [0-9]
@@ -116,12 +118,6 @@ L?\"(\\.|[^\\"])*\"	{/* TODO process string literal */; return(STRING_LITERAL);}
 "?"			   {return('?');}
 
 [ \a\b\t\v\f\n\r]		{/* ignore new lines and special sequences */}
-.			              {/* ignore bad characters */}
+.			              {std::cerr << "Unknown token: " << yytext << std::endl; return(UNKNOWN);}
 
 %%
-
-void yyerror (char const *s)
-{
-  fprintf(stderr, "Lexing error: %s\n", s);
-  exit(1);
-}

src/parser.y

@@ -4,21 +4,26 @@
 // rename parser_full.y to parser.y once you're happy with
 // how this example works.
 
-%code requires{
-    #include "ast.hpp"
-
+%code requires {
+	#include "ast.hpp"
 	using namespace ast;
 
-    extern Node* g_root;
-    extern FILE* yyin;
-    int yylex(void);
-    void yyerror(const char*);
+	extern int yylineno;
+	extern char* yytext;
+	extern Node* g_root;
+	extern FILE* yyin;
+
+	int yylex(void);
+	void yyerror(const char*);
 	int yylex_destroy(void);
 }
 
-%union{
-  Node*				node;
-  NodeList*			node_list;
+%define parse.error detailed
+%define parse.lac full
+
+%union {
+  Node*				    node;
+  NodeList*			  node_list;
   int          		number_int;
   double       		number_float;
   std::string*		string;
@@ -33,6 +38,7 @@
 %token CHAR SHORT INT LONG SIGNED UNSIGNED FLOAT DOUBLE CONST VOLATILE VOID
 %token STRUCT UNION ENUM ELLIPSIS
 %token CASE DEFAULT IF ELSE SWITCH WHILE DO FOR GOTO CONTINUE BREAK RETURN
+%token UNKNOWN
 
 %type <node> translation_unit external_declaration function_definition primary_expression postfix_expression
 %type <node> unary_expression cast_expression multiplicative_expression additive_expression shift_expression relational_expression
@@ -51,7 +57,7 @@
 %%
 
 ROOT
-    : translation_unit { g_root = $1; }
+	: translation_unit { g_root = $1; }
 
 translation_unit
 	: external_declaration { $$ = $1; }
@@ -185,18 +191,28 @@ expression
 
 %%
 
+void yyerror (const char *s)
+{
+  std::cerr << "Error: " << s << " at line " << yylineno;
+  std::cerr << " near '" << yytext << "'" << std::endl;
+  std::exit(1);
+}
+
 Node* g_root;
 
 NodePtr ParseAST(std::string file_name)
 {
   yyin = fopen(file_name.c_str(), "r");
-  if(yyin == NULL){
+  if (yyin == nullptr) {
     std::cerr << "Couldn't open input file: " << file_name << std::endl;
-    exit(1);
+    std::exit(1);
   }
+
   g_root = nullptr;
   yyparse();
+
   fclose(yyin);
   yylex_destroy();
+
   return NodePtr(g_root);
 }

src/parser_full.y.example

@@ -1,19 +1,24 @@
 // Adapted from: https://www.lysator.liu.se/c/ANSI-C-grammar-y.html
 
-%code requires{
-    #include "ast.hpp"
-
+%code requires {
+	#include "ast.hpp"
 	using namespace ast;
 
-    extern Node* g_root;
-    extern FILE* yyin;
-    int yylex(void);
-    void yyerror(const char*);
+	extern int yylineno;
+	extern char* yytext;
+	extern Node* g_root;
+	extern FILE* yyin;
+
+	int yylex(void);
+	void yyerror(const char*);
 	int yylex_destroy(void);
 }
 
+%define parse.error detailed
+%define parse.lac full
+
 // Represents the value associated with any kind of AST node.
-%union{
+%union {
   Node*        	node;
   NodeList*    	node_list;
   int          	number_int;
@@ -30,6 +35,7 @@
 %token CHAR SHORT INT LONG SIGNED UNSIGNED FLOAT DOUBLE CONST VOLATILE VOID
 %token STRUCT UNION ENUM ELLIPSIS
 %token CASE DEFAULT IF ELSE SWITCH WHILE DO FOR GOTO CONTINUE BREAK RETURN
+%token UNKNOWN
 
 %type <node> translation_unit external_declaration function_definition primary_expression postfix_expression argument_expression_list
 %type <node> unary_expression cast_expression multiplicative_expression additive_expression shift_expression relational_expression
@@ -462,18 +468,28 @@ jump_statement
 
 %%
 
+void yyerror (const char *s)
+{
+  std::cerr << "Error: " << s << " at line " << yylineno;
+  std::cerr << " near '" << yytext << "'" << std::endl;
+  std::exit(1);
+}
+
 Node* g_root;
 
 NodePtr ParseAST(std::string file_name)
 {
   yyin = fopen(file_name.c_str(), "r");
-  if(yyin == NULL){
+  if (yyin == nullptr) {
     std::cerr << "Couldn't open input file: " << file_name << std::endl;
-    exit(1);
+    std::exit(1);
   }
+
   g_root = nullptr;
   yyparse();
+
   fclose(yyin);
   yylex_destroy();
+
   return NodePtr(g_root);
 }