added yacc and lex example to ast-lex-yacc

Makefile

@@ -1,21 +0,0 @@
-
-BUILDDIR = build
-TARGET_SRC = main
-
-build: mkdir main
-all: mkdir main run
-
-mkdir:	# create build directory
-	mkdir -p $(BUILDDIR)
-
-run:	# run binary
-	./$(BUILDDIR)/main
-
-main: lex.yy.c	# compile c file
-	cc $(BUILDDIR)/lex.yy.c -o $(BUILDDIR)/$(TARGET_SRC) -lfl
-
-lex.yy.c: main.lex # generate c file
-	flex -o $(BUILDDIR)/lex.yy.c $(TARGET_SRC).lex
-
-clean: # wipe the build directory
-	rm -f $(BUILDDIR)/*

ast-lex-yacc/Makefile

@@ -0,0 +1,26 @@
+
+BUILDDIR = build
+TARGET_SRC = main
+
+build: mkdir main
+all: mkdir main run
+
+mkdir:	# create build directory
+	mkdir -p $(BUILDDIR)
+
+run:	# run binary
+	./$(BUILDDIR)/main
+
+main: lex.yy.c	yacc.yy.c
+	cc $(BUILDDIR)/yacc.yy.c $(BUILDDIR)/lex.yy.c -o $(BUILDDIR)/$(TARGET_SRC) -lfl
+
+# generate c file for lex
+lex.yy.c:
+	flex -o $(BUILDDIR)/lex.yy.c $(TARGET_SRC).l
+
+# generate c file for yacc
+yacc.yy.c:
+	yacc -d -o $(BUILDDIR)/yacc.yy.c $(TARGET_SRC).y
+
+clean: # wipe the build directory
+	rm -f $(BUILDDIR)/*

ast-lex-yacc/main.l

@@ -0,0 +1,37 @@
+%option noyywrap
+%{
+    #include <stdio.h>
+    #include "yacc.yy.h"
+    #define YYDEBUG 1
+    int yyLineNumber = 1;
+%}
+
+%%
+\n              yyLineNumber++;
+0|[1-9][0-9]*   return(Number);       // integer numbers
+"VAR"|"var"     return(Variable);
+"INT"|"int"     return(Integer);
+[a-zA-Z]+       return(Ident);
+","             return(',');
+":"             return(':');
+";"             return(';');
+"+"             return('+');
+"-"             return('-');
+"("             return('(');
+")"             return(')');
+[ \t]
+.               print_stdout("unknown Symbol");
+%%
+
+/*
+int main()
+{
+    printf("Programm eingeben: \n");
+    yylex();
+    return 0;
+}
+*/
+
+int print_stdout(char token[]) {
+    printf("\nFLEX/[INF] >>> Token (%d) AS %s ```%s```\n", yyLineNumber, token, yytext);
+}

ast-lex-yacc/main.y

@@ -0,0 +1,28 @@
+%{
+    #include <stdio.h>
+    extern int yylineno;
+%}
+
+%token Variable
+%token Integer
+%token Ident
+%token Number
+
+%%
+program:    decllist exprlist;
+decllist:   decl ';' | decllist decl ';' | /* empty */ | error ';' { yyerror(" im Deklarationsteil\n"); };
+decl:       Variable idlist ':' type;
+idlist:     Ident | idlist ',' Ident;
+type:       Integer;
+exprlist:   /* empty */ ;
+%%
+
+int main() {
+    printf("Bitte geben Sie ein Program ein: \n");
+    yyparse();
+    return 0;
+}
+
+int yyerror(char *s) {
+    printf("YACC/[ERR] >>> Failed parsing grammar (%d): ```%s```", yylineno, s);
+}