From a4c91889a67ec12057d08d21a81a1f4ed677fc67 Mon Sep 17 00:00:00 2001
From: Georgi Stefanov <geosteffanov@gmail.com>
Date: Thu, 25 Oct 2018 12:54:32 +0300
Subject: 81319 golang2html lexer (#20)

* Add highlighter for golang

* Add readme with instructions

* Fix readme
---
 homework/81319/golang2html/README.md        |  30 +++++++
 homework/81319/golang2html/golang2html.flex | 121 ++++++++++++++++++++++++++++
 homework/81319/golang2html/hello_world.go   |  21 +++++
 3 files changed, 172 insertions(+)
 create mode 100644 homework/81319/golang2html/README.md
 create mode 100644 homework/81319/golang2html/golang2html.flex
 create mode 100644 homework/81319/golang2html/hello_world.go

diff --git a/homework/81319/golang2html/README.md b/homework/81319/golang2html/README.md
new file mode 100644
index 0000000..63c5f53
--- /dev/null
+++ b/homework/81319/golang2html/README.md
@@ -0,0 +1,30 @@
+# How-to guide
+
+## Compiling the highlighter
+
+1. Transpile flex file to c file
+```
+flex golang2html.flex
+```
+
+2. Compile the produced output file
+
+```
+gcc lex.yy.c -o lexer
+```
+
+The produced output is the 'lexer' file. You use it to highlight
+your own golang source files.
+
+## Highlighting Golang code
+
+1. Create your own golang source file with whatever name you wish. For
+this example, let your golang source be 'hello_world.go'.
+
+2. Produce the highlighted html output
+
+```
+./lexer hello_world.go > hello_world.html
+```
+
+## Enjoy
diff --git a/homework/81319/golang2html/golang2html.flex b/homework/81319/golang2html/golang2html.flex
new file mode 100644
index 0000000..9501645
--- /dev/null
+++ b/homework/81319/golang2html/golang2html.flex
@@ -0,0 +1,121 @@
+/* golang scanner */
+
+%{
+#define YY_NO_UNISTD_H
+%}
+
+DIGIT    [0-9]
+ID       [a-zA-Z_][a-zA-Z0-9_]*
+STRQ     '([^\']|(\\\'))*'
+STRDQ    \"([^\"]|(\\\"))*\"
+
+%%
+
+{DIGIT}+    {
+            printf("<span class=\"number\">%s</span>", yytext);
+            }
+
+{DIGIT}+"."{DIGIT}*        {
+            printf("<span class=\"number\">%s</span>", yytext);
+            }
+
+break|default|func|interface|select|case|defer|go|map|struct {
+        printf("<span class=\"keyword\">%s</span>", yytext);
+}
+
+chan|else|goto|package|switch|const|fallthrough|if|range|type|continue|for|import|return|var {
+           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);
+}
+
+"<="|"["|"]"|"*"|"^"|"*="|"^="|"<-"|">"|">="|"{"|"}"|"/"|"<<"|"/=" {
+    printf("<span class=\"operator\">%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;
+}
+
+void printStyles() {
+    puts(
+            "    <style>"
+            "        .identifier {"
+            "            color: brown;"
+            "        }"
+            "        .keyword {"
+            "            color: #1fbfe2;"
+            "        }"
+            "        .number {"
+            "            color: blue;"
+            "        }"
+            "        .string {"
+            "            color: green;"
+            "        }"
+            "        .operator {"
+            "            color: #db184c;"
+            "            font-style: bold;"
+            "        }"
+            "    </style>"
+    );
+}
+
+void printHtmlHeader() {
+       puts(
+                   "<head>"
+                   "    <title>hello_world.go</title>"
+       );
+       printStyles();
+       puts(
+        "</head>"
+       );
+}
+
+void printBody() {
+    puts(
+      "<body bgcolor=\"#e2cdb7\">"
+      "    <pre class=\"code\">"
+      );
+      yylex();
+      puts("</pre></body>");
+}
+
+
+void printHTML() {
+    puts(
+      "<!doctype>"
+      "<html>"
+    );
+    printHtmlHeader();
+    printBody();
+    puts("</html>");
+}
+
+int main(int argc, const char* argv[])
+{
+    ++argv, --argc;  /* skip over program name */
+    if ( argc > 0 )
+            yyin = fopen( argv[0], "r" );
+    else
+            yyin = stdin;
+
+    printHTML();
+    return 0;
+}
diff --git a/homework/81319/golang2html/hello_world.go b/homework/81319/golang2html/hello_world.go
new file mode 100644
index 0000000..0a31497
--- /dev/null
+++ b/homework/81319/golang2html/hello_world.go
@@ -0,0 +1,21 @@
+package main
+
+import (
+	"fmt"
+)
+
+type HelloWorlder struct {
+	message string
+}
+
+func (hw *HelloWorlder) greet() {
+	fmt.Println(hw.message)
+}
+
+func main() {
+	helloWorlder := &HelloWorlder{
+		message: "Hello, world!",
+	}
+
+	helloWorlder.greet()
+}
\ No newline at end of file
-- 
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