How to use faces to enhance text

Question

I'm writing some very simple code to get data from a web api, i then parse the response and output the result in a buffer.

By default this text is very flat, how can i add keyword highlighting that follows the current theme's colourscheme?

For example, the text in the buffer:

Title

• Keyword1: data1
• Keyword2: data2

How can i define, and most importantly apply faces(i think) to the keywords?

Answer 1

You have to use the propertize method for that.

For exemple, in your case, to use the font-lock-builtin-face on the Keyword words, you can do:

(save-excursion
  (goto-char (point-min))
    (while (re-search-forward "^Keyword[0-9]:" nil t)
      (replace-match (propertize (match-string 0) 'face 'font-lock-builtin-face))))