Add gemini lexer

lua/lexers/gemini.lua

@@ -0,0 +1,48 @@
+-- Copyright 2006-2017 Mitchell mitchell.att.foicica.com. See LICENSE.
+-- Markdown LPeg lexer.
+-- Copyright 2020 Haelwenn (lanodan) Monnier <[email protected]>
+-- Gemini / Gemtext LPeg lexer.
+-- See https://gemini.circumlunar.space/docs/specification.html
+
+local l = require('lexer')
+local token, word_match = l.token, l.word_match
+local P, R, S = lpeg.P, lpeg.R, lpeg.S
+
+local M = {_NAME = 'gemini'}
+
+local ws = token(l.WHITESPACE, S(' \t')^1 + S('\v\r\n')^1)
+
+local link = token('link', l.starts_line('=>') * l.nonnewline^0)
+
+-- Should only match ``` at start of line
+local pre = token('pre', l.delimited_range('```', false, true))
+
+local header = token('h3', l.starts_line('###') * l.nonnewline^0) +
+               token('h2', l.starts_line('##') * l.nonnewline^0) +
+               token('h1', l.starts_line('#') * l.nonnewline^0)
+
+local list = token('list', l.starts_line('*') * l.nonnewline^0)
+
+local blockquote = token(l.STRING, l.starts_line('>') * l.nonnewline^0)
+
+M._rules = {
+  {'header', header},
+  {'list', list},
+  {'blockquote', blockquote},
+  {'pre', pre},
+  {'whitespace', ws},
+  {'link', link}
+}
+
+local font_size = 10
+local hstyle = 'fore:red'
+M._tokenstyles = {
+  h3 = hstyle..',size:'..(font_size + 3),
+  h2 = hstyle..',size:'..(font_size + 4),
+  h1 = hstyle..',size:'..(font_size + 5),
+  pre = l.STYLE_EMBEDDED..',eolfilled',
+  link = 'underlined',
+  list = l.STYLE_CONSTANT
+}
+
+return M

lua/plugins/filetype.lua

@@ -149,6 +149,10 @@ vis.ftdetect.filetypes = {
 	gap = {
 		ext = { "%.g$", "%.gd$", "%.gi$", "%.gap$" },
 	},
+	gemini = {
+		ext = { "%.gmi" },
+		mime = { "text/gemini" },
+	},
 	gettext = {
 		ext = { "%.po$", "%.pot$" },
 	},