added JavaScript flex based highlighter

1 files changed, 76 insertions, 0 deletions

diff --git a/demo/flex/js2html.flex b/demo/flex/js2html.flex
new file mode 100644
index 0000000..738895e
--- /dev/null
+++ b/demo/flex/js2html.flex
@@ -0,0 +1,76 @@
+/* scanner for a toy JavaScript-like language */
+
+%{
+%}
+
+DIGIT    [0-9]
+ID       [a-z_$][a-z0-9_$]*
+STRQ     '([^\']|(\\\'))*'
+STRDQ    "([^\"]|(\\\"))*"
+
+%%
+
+{DIGIT}+    {
+            printf("<span class=\"number\">%s</span>", yytext);
+            }
+
+{DIGIT}+"."{DIGIT}*        {
+            printf("<span class=\"number\">%s</span>", yytext);
+            }
+
+if|else|for|while|do|break|switch|case|function|return|new|delete|try|throw|catch|class|public|private {
+    printf("<span class=\"keyword\">%s</span>", yytext);
+}
+
+{ID}    printf("<span class=\"identifier\">%s</span>", yytext);
+{STRQ}|{STRDQ}        printf("<span class=\"string\">%s</span>", yytext);
+
+"."|"+"|"-"|"*"|"/"|"="|"!"|">"|"<"|"!=="|"==="|">="|"<="|"++"|"--"|"=>"   printf("<span class=\"operator\">%s</span>", yytext);
+
+[;(){}:? \t\n]+          printf("%s", yytext); /* echo the rest */
+
+.           printf( "Unrecognized character: %s\n", yytext );
+
+%%
+
+int yywrap()
+{
+    return 1;
+}
+
+
+int main(int argc, const char* argv[])
+{
+    ++argv, --argc;  /* skip over program name */
+    if ( argc > 0 )
+            yyin = fopen( argv[0], "r" );
+    else
+            yyin = stdin;
+
+    puts(
+        "<!doctype>"
+        "<html>"
+        "<head>"
+        "    <title>hello.js</title>"
+        "    <style>"
+        "        .keyword {"
+        "            color: red;"
+        "        }"
+        "        .number {"
+        "            color: blue;"
+        "        }"
+        "        .string {"
+        "            color: green;"
+        "        }"
+        "        .operator {"
+        "            font-style: bold;"
+        "        }"
+        "    </style>"
+        "</head>"
+        "<body>"
+        "    <pre class=\"code\">"
+        );
+    yylex();
+    puts("</pre></body></html>");
+    return 0;
+}