Add solutions to the homework

python.flx

@@ -0,0 +1,73 @@
+%option noyywrap
+
+%{
+
+#define PRINTJ(format, str, v) printf("%s\t" format "\n", str, v)
+#define PRINT(format, str, v) { int i; printf(str); i = 1 + (16 - strlen(str)) / 8; while(i--) putc('\t', yyout); printf(format "\n", v); }
+#define PRINTD(name) PRINT("%s", name, yytext)
+
+int indent_stack[128];
+int indent_sp = 0;
+
+void handle_indent(int l) {
+    while(l != indent_stack[indent_sp]) {
+        if(l > indent_stack[indent_sp]) {
+            indent_stack[++indent_sp] = l;
+            printf("INDENT\n");
+        } else {
+            indent_sp--;
+            printf("DEDENT\n");
+        }
+    }
+}
+
+%}
+
+%%
+
+^(#[^\n]*)?\n[^ ]      { handle_indent(0); unput(yytext[yyleng-1]); }
+^(#[^\n]*)?\n          {}
+\n[^ ]                 { printf("NEWLINE\n"); handle_indent(0); unput(yytext[1]); }
+\n                     printf("NEWLINE\n");
+
+<<EOF>>                { handle_indent(0); return 0; }
+
+^[ ]*                  handle_indent(yyleng);
+[ ]*                   {}
+-?[0-9]+\.[0-9]*       PRINT("%.6g", "FLOAT", atof(yytext));
+[0-9]+                 PRINTD("INTEGER");
+True|False             PRINT("%d", "BOOLEAN", yytext[0] == 'T');
+and                    PRINTD("AND");
+break                  PRINTD("BREAK");
+def                    PRINTD("DEF");
+elif                   PRINTD("ELIF");
+else                   PRINTD("ELSE");
+for                    PRINTD("FOR");
+if                     PRINTD("IF");
+not                    PRINTD("NOT");
+or                     PRINTD("OR");
+return                 PRINTD("RETURN");
+while                  PRINTD("WHILE");
+[a-zA-Z_][a-zA-Z_0-9]* PRINTD("IDENTIFIER");
+"="                    PRINTD("ASSIGN");
+"+"                    PRINTD("PLUS");
+"-"                    PRINTD("MINUS");
+"*"                    PRINTD("TIMES");
+"/"                    PRINTD("DIVIDEDBY");
+"=="                   PRINTD("EQ");
+"!="                   PRINTD("NEQ");
+">"                    PRINTD("GT");
+">="                   PRINTD("GTE");
+"<"                    PRINTD("LT");
+"<="                   PRINTD("LTE");
+"("                    PRINTD("LPAREN");
+")"                    PRINTD("RPAREN");
+","                    PRINTD("COMMA");
+":"                    PRINTD("COLON");
+
+%%
+
+int main() {
+    indent_stack[0] = 0;
+    yylex();
+}

test.sh

@@ -0,0 +1,9 @@
+flex python.flx && gcc lex.yy.c
+mkdir -p real_output
+mkdir -p diff_results
+
+for file in $(ls testing_code); do
+    name=$(echo $file | awk -F'[.]' '{print $1}')
+    ./a.out < testing_code/$file > real_output/$name.out
+    diff example_output/$name.out real_output/$name.out > diff_results/$name.diff
+done