init t-08

Makefile

+all: tokens
+
+OBJS = tokens.o  
+
+LLVMCONFIG = llvm-config-6.0
+CPPFLAGS = -g `$(LLVMCONFIG) --cppflags` -std=c++11
+LDFLAGS = `$(LLVMCONFIG) --ldflags` -rdynamic
+LIBS = `$(LLVMCONFIG) --libs`
+
+clean:
+	$(RM) -rf tokens.cpp tokens.hpp tokens $(OBJS)
+
+tokens.cpp: tokens.l
+	flex --header-file=$(subst .cpp,.hpp,$@) -o $@ $^
+
+tokens.hpp: tokens.cpp
+
+%.o: %.cpp
+	$(CXX) -c $(CPPFLAGS) -o $@ $<
+
+
+tokens: $(OBJS)
+	$(CXX) -o $@ $(OBJS) $(LIBS) $(LDFLAGS)
+
+test: tokens example.txt
+	cat example.txt | ./$^
+
+distclean: clean
+	$(RM) -rf .depend ./tokens.cpp ./tokens.hpp
+
+.PHONY: clean distclean
+
+depend: .depend
+
+.depend: tokens.cpp tokens.hpp
+	$(CXX) `$(LLVMCONFIG) --cppflags` $(FLAGS) $(INCLUDE) -M *.cpp > .depend || true
+	$(CXX) `$(LLVMCONFIG) --cppflags` $(FLAGS) $(INCLUDE) -M *.hpp >> .depend || true
+
+-include .depend
+

example.txt

+extern int printi(int val);
+
+int do_math(int a) {
+  int x = a * 5;
+  return x + 3;
+}
+
+printi(do_math(8)-1);

tokens.l

+%{
+#include <cstdio>
+#include <string>
+
+ /* Will later be replaced by parser definitions! */
+ int yylval;
+ enum token_t
+  {
+    TINT_T = 258,
+    TVOID_T = 259,
+    TIDENTIFIER = 260,
+    TINTEGER = 261,
+    TASSIGN = 262,
+    TNE = 263,
+    TLT = 264,
+    TLE = 265,
+    TGT = 266,
+    TGE = 267,
+    TEQ = 268,
+    TLPAREN = 269,
+    TRPAREN = 270,
+    TLBRACE = 271,
+    TRBRACE = 272,
+    TSEMICOL = 273,
+    TCOMMA = 274,
+    TPLUS = 275,
+    TMINUS = 276,
+    TMUL = 277,
+    TDIV = 278,
+    TRETURN = 279,
+    TEXTERN = 280,
+    TIF = 281,
+    TELSE = 282,
+    UMINUS = 283,
+    TNONE = 0
+};
+
+%}
+
+%option noyywrap
+%option yylineno
+
+%%
+
+[ \t\n]                         ;
+"//".*$                         ;
+"extern"                        {return TEXTERN;}
+"return"                        {return TRETURN;}
+"int"                           {return TINT_T;}
+"if"                            {return TIF;}
+"else"                          {return TELSE;}
+[a-zA-Z_][a-zA-Z0-9_]*          {return TIDENTIFIER;}
+[0-9]+                          {yylval = std::stoi(yytext);return TINTEGER;}
+
+"="                             {return TASSIGN;}
+"=="                            {return TEQ;}
+"!="                            {return TNE;}
+"<"                             {return TLT;}
+"<="                            {return TLE;}
+">"                             {return TGT;}
+">="                            {return TGE;}
+
+"("                             {return TLPAREN;}
+")"                             {return TRPAREN;}
+"{"                             {return TLBRACE;}
+"}"                             {return TRBRACE;}
+
+","                             {return TCOMMA;}
+";"                             {return TSEMICOL;}
+
+"+"                             {return TPLUS;}
+"-"                             {return TMINUS;}
+"*"                             {return TMUL;}
+"/"                             {return TDIV;}
+
+<<EOF>>                         {return TNONE;}
+
+.                               {fprintf(stderr,"Unknown token '%s' in line %d!\n",yytext,yylineno); yyterminate();}
+
+%%
+
+int main(){
+  int token;
+  while(TNONE!=(token=yylex())){
+    printf("read '%s' of length %d -- which is of type %d (value is %d)\n",yytext,yyleng,token,yylval);
+  }
+  return 0;
+}
+