Add foldable blocks in Golang 2 highlighter (#33)

* initial commit

* Add implementation using concatenation

* Added block collapsing

* Finish block collapsing

* Fix nested blocks and + -> - when collapsing

* Remove unnecessary files.

* Add readme

1 files changed, 243 insertions, 0 deletions

diff --git a/homework/81319/golang2html_code_fold/parser.y b/homework/81319/golang2html_code_fold/parser.y
new file mode 100644
index 0000000..fcd4834
--- /dev/null
+++ b/homework/81319/golang2html_code_fold/parser.y
@@ -0,0 +1,243 @@
+%{
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+int yylex();
+int yyerror(const char* error);
+#define YYDEBUG 1
+
+char* concatenate(char* first, char* second) {
+    int firstlen = strlen(first);
+    int secondlen = strlen(second);
+    char* result;
+    result = malloc(firstlen + secondlen + 1);
+    strcpy(result, first);
+    strcat(result, second);
+
+    return result;
+}
+
+void printStyles() {
+    puts(
+            "    <style>"
+            "        .identifier {"
+            "            color: brown;"
+            "        }"
+            "        .keyword {"
+            "            color: #1fbfe2;"
+            "        }"
+            "        .number {"
+            "            color: blue;"
+            "        }"
+            "        .string {"
+            "            color: green;"
+            "        }"
+            "        .operator {"
+            "            color: #db184c;"
+            "            font-style: bold;"
+            "        }"
+            "        .collapsible {"
+            "            background-color: #777;"
+            "            color: white;"
+            "            cursor: pointer;"
+            "            padding: 2px;"
+            "            width: 2%;"
+            "            border: none;"
+            "            text-align: center;"
+            "            outline: none;"
+            "            font-size: 15px;"
+            "        }"
+
+            "        .active, .collapsible:hover {"
+            "            background-color: #555;"
+            "        }"
+
+
+            "     </style>"
+    );
+}
+
+void printCollapsableScript() {
+        puts(
+                "<script>"
+                "var coll = document.getElementsByClassName(\"collapsible\");\n"
+                "var i;\n"
+                "\n"
+                "for (i = 0; i < coll.length; i++) {\n"
+                  "coll[i].addEventListener(\"click\", function() {\n"
+                    "this.classList.toggle(\"active\");\n"
+                    "var content = this.nextElementSibling;\n"
+                    "if (content.style.display === \"block\") {\n"
+                      "content.style.display = \"none\";\n"
+                      "this.innerHTML=\"+\""
+                    "} else {\n"
+                      "content.style.display = \"block\";\n"
+                      "this.innerHTML=\"-\""
+                    "}\n"
+                  "});\n"
+                "}\n"
+                "</script>"
+        );
+}
+
+char* stylize(char* text, char* style) {
+    char* result = concatenate("<span class=\"", style);
+    result = concatenate(result, "\">");
+    result = concatenate(result, text);
+    result = concatenate(result, "</span>");
+
+    return result;
+}
+
+char* collapsableBlock(char* text) {
+        char* result = concatenate("<button class=\"collapsible\">+</button>", "<div class=\"content\">");
+        result = concatenate(result, text);
+        result = concatenate(result, "</div>");
+
+        return result;
+}
+
+void printNumber(char* text) {
+   char* style = stylize(text, "number");
+   printf("%s", style);
+}
+
+
+void printIdentifier(char* text) {
+   char* style = stylize(text, "identifier");
+   printf("%s", style);
+}
+
+void printKeyword(char* text) {
+   char* style = stylize(text, "keyword");
+   printf("%s", style);
+}
+
+void printString(char* text) {
+   char* style = stylize(text, "string");
+   printf("%s", style);
+}
+
+void printOperator(char* text) {
+     char* style = stylize(text, "operator");
+     printf("%s", style);
+}
+
+void printMisc(char* text) {
+    printf("%s", text);
+}
+
+void printUnrecognized(char* text) {
+    printf("Unrecognized token: %s", text);
+}
+
+void printBraces(char* text) {
+    printf("%s", text);
+}
+
+%}
+
+%start input
+
+
+%token NUMBER
+%token KEYWORD
+%token STRING
+%token STRING_DQ
+%token IDENTIFIER
+%token OPERATOR
+%token MISC
+%token UNRECOGNIZED
+%token LCURLY
+%token RCURLY
+
+%union {
+    char* strval;
+}
+
+%type <strval> input expr_list expr token_sequence token NUMBER KEYWORD STRING STRING_DQ IDENTIFIER OPERATOR MISC UNRECOGNIZED LCURLY RCURLY
+
+
+%%
+
+input:  /* empty */ { printf("empty\n"); }
+    | expr_list { printf("%s", $$); }
+    ;
+
+expr_list: expr expr_list { $$ = concatenate($1, $2); }
+        | expr { $$ = $1; }
+        ;
+
+expr: token_sequence
+        | LCURLY expr_list RCURLY {
+                        char* collapsable = collapsableBlock($2);
+                        $$ = concatenate("{", collapsable);
+                        $$ = concatenate($$, "}");
+                  }
+        | LCURLY RCURLY { $$ = concatenate("{", "}"); }
+        ;
+
+
+token_sequence: token_sequence token { $$ = concatenate($1, $2); }
+        | token { $$ = $1; }
+        ;
+
+token: NUMBER { $$ = stylize($1, "number"); }
+    | KEYWORD { $$ = stylize($1, "keyword"); }
+    | STRING { $$ = stylize($1, "string"); }
+    | STRING_DQ { $$ = stylize($1, "string"); }
+    | IDENTIFIER { $$ = stylize($1, "identifier"); }
+    | OPERATOR { $$ = stylize($1, "operator"); }
+    | MISC { $$ = $1; }
+    | UNRECOGNIZED { $$ = $1 }
+    ;
+
+%%
+
+int yyerror(const char* error)
+{
+    extern int current_line;
+    fprintf(stderr, "input:%d: error: %s\n", current_line, error);
+    return 0;
+}
+
+
+void printHtmlHeader() {
+       puts(
+                   "<head>"
+                   "    <title>hello_world.go</title>"
+       );
+       printStyles();
+       puts(
+        "</head>"
+       );
+}
+
+
+
+void printBody() {
+    puts(
+      "<body bgcolor=\"#e2cdb7\">"
+      "    <pre class=\"code\">"
+      );
+      yyparse();
+      puts("</pre></body>");
+}
+
+void printHTML() {
+    puts(
+      "<!doctype>"
+      "<html>"
+    );
+    printHtmlHeader();
+    printBody();
+    printCollapsableScript();
+    puts("</html>");
+}
+
+
+int main(int argc, const char* argv[])
+{
+    printHTML();
+    return 0;
+}