Add support for processing legacy nroff(1) output

Alhadis · Jun 2, 2018 · 7a756b9 · 7a756b9
1 parent cdf9d5c
commit 7a756b9
Show file tree

Hide file tree

Showing 6 changed files with 843 additions and 9 deletions.
diff --git a/bin/html-tty b/bin/html-tty
@@ -13,10 +13,11 @@ new Promise(resolve => {
  process.stdin.on("readable", () => {
  const chunk = process.stdin.read();
  null !== chunk ? input += chunk : resolve(input);
- })
+ });
  }
 }).then(data => {
- let output = htmlTTY.process(data);
+ const isRaw = /\x08/.test(data);
+ let output = htmlTTY.process(data, isRaw);
  if(process.stdout.isTTY)
  output = output
  .replace(/^\n+/, "")

diff --git a/lib/postproc/html-tty.js b/lib/postproc/html-tty.js
@@ -16,15 +16,25 @@ class HTMLTTY extends Postprocessor {
  }
 
 
- process(data){
+ process(data, raw = false){
  this.reset();
- super.process(data);
- if(null !== this.page){
- this.output += this.page.toString().replace(/^ *\n/, "");
- this.page = null;
+
+ // Raw text printed by older nroff(1) versions
+ if(raw){
+ this.output = new TextGrid().read(data).toString();
+ return this.output;
+ }
+
+ // Ditroff (intermediate troff output)
+ else{
+ super.process(data);
+ if(null !== this.page){
+ this.output += this.page.toString().replace(/^ *\n/, "");
+ this.page = null;
+ }
+ this.output = this.output.replace(/\s+$/, "");
+ return this.output;
  }
- this.output = this.output.replace(/\s+$/, "");
- return this.output;
  }
 
 

diff --git a/lib/text-grid.js b/lib/text-grid.js
@@ -382,6 +382,130 @@ class TextGrid{
  : toPlainText;
  return this.data.map(fn).join("\n");
  }
+
+
+ read(text){
+ if(!text) return this;
+ let yOffset = 0;
+ const {length} = text;
+ for(let i = 0; i < length; ++i){
+ const next = text.charCodeAt(i + 1) || -1;
+ switch(text.charCodeAt(i)){
+
+ // Backspace
+ case 0x08:
+ this.left();
+ break;
+
+ // Horizontal tab
+ case 0x09:
+ break;
+
+ // Vertical tab ("Line tabulation")
+ case 0x0B:
+ this.up();
+ break;
+
+ // Carriage return
+ case 0x0D:
+ if(0x0A === next)
+ continue;
+ this.x = 0;
+ break;
+
+ // Newline
+ case 0x0A:
+ case 0x85:
+ this.write("\n");
+ break;
+
+ // Form feed
+ case 0x0C:
+ this.down();
+ break;
+
+ // Shift out: Enable reverse video
+ case 0x0E:
+ break;
+
+ // Shift in: Disable reverse video
+ case 0x0F:
+ break;
+
+ // Space
+ case 0x20:
+ this.right();
+ break;
+
+ // Escape
+ case 0x1B:
+ switch(next){
+ // Full-reverse line feed
+ case 0x07:
+ case 0x37:
+ this.up();
+ yOffset = 0;
+ ++i;
+ break;
+
+ // Half-reverse line feed
+ case 0x08:
+ case 0x38:
+ ++i;
+ yOffset -= 0.5;
+ if(-1 === yOffset){
+ yOffset = 0;
+ this.up();
+ }
+ break;
+
+ // Half-forward line feed
+ case 0x09:
+ case 0x39:
+ ++i;
+ yOffset += 0.5;
+ if(1 === yOffset){
+ yOffset = 0;
+ this.down();
+ }
+ break;
+
+ // CSI introducer (omitted for now)
+ case 0x5B:
+ break;
+ }
+ break;
+
+ // Anything else
+ default:{
+ const char = this.currentChar;
+
+ if(char && /\S/.test(char)){
+ const prevFont = this.data[this.y][this.x][1];
+
+ // Underline
+ if("_" === char || "_" === text[i]){
+ this.font = ("B" === prevFont || "BI" === prevFont) ? "BI" : "I";
+ this.write("_" === char ? text[i] : char);
+ this.font = "R";
+ }
+
+ // Embolden
+ else if(/\S/.test(text[i]) && text[i] === char){
+ this.font = ("I" === prevFont || "BI" === prevFont) ? "BI" : "B";
+ this.write(char);
+ this.font = "R";
+ }
+
+ // Print normally
+ else this.write(text[i]);
+ }
+ else this.write(text[i]);
+ }
+ }
+ }
+ return this;
+ }
 
 
  write(text){

diff --git a/test/1-html-tty.js b/test/1-html-tty.js
@@ -36,6 +36,13 @@ describe("HTMLTTY", () => {
  });
  }
 
+ it("formats raw nroff(1) output correctly", () => {
+ const source = read("teletype.txt");
+ const expected = read("teletype.html");
+ const result = [tmplHeader, htmlTTY.process(source, true), tmplFooter, ""].join("\n");
+ expect(result).to.eql(expected);
+ });
+
  it("can be used as a command-line postprocessor", () => {
  return new Promise((resolve, reject) => {
  const {exec} = require("child_process");