1 file changed, 77 insertions, 0 deletions
diff --git a/tests/extensions/fake-lexers/lexer.lua b/tests/extensions/fake-lexers/lexer.lua
new file mode 100644
index 0000000..adf7d5b
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+++ b/tests/extensions/fake-lexers/lexer.lua
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+-- A miniature stand-in for the Scintillua lexer module, just enough for the
+-- syntax-highlight checks to drive every path through the filter without the
+-- real collection installed. load() hands out one of the toy lexers below by
+-- name and detect() recognises a single filename suffix, so a check can tell
+-- the detection path apart from the extension path by which lexer ends up
+-- running. Anything the filter treats as optional, a lexer that will not
+-- load or one that raises while lexing, has a name here too.
+
+local M = {}
+
+-- Tokens come back the way Scintillua returns them, one flat list of a tag
+-- name and the position just past the token it names. Letter runs are
+-- keywords, digit runs are numbers, a single quoted run carries a dotted tag
+-- so the dotted first component lookup gets exercised, and any other byte is
+-- whitespace, which maps to no css class.
+local function lex_words(self, text)
+	local tokens = {}
+	local pos = 1
+	while pos <= #text do
+		local start, stop = text:find("^%a+", pos)
+		if not start then
+			start, stop = text:find("^%d+", pos)
+			if start then
+				tokens[#tokens + 1] = "number"
+			else
+				start, stop = text:find("^'[^']*'", pos)
+				if start then
+					tokens[#tokens + 1] = "string.double"
+				else
+					stop = pos
+					tokens[#tokens + 1] = "whitespace"
+				end
+			end
+		else
+			tokens[#tokens + 1] = "keyword"
+		end
+		tokens[#tokens + 1] = stop + 1
+		pos = stop + 1
+	end
+	return tokens
+end
+
+-- Tags only the first four bytes and stops, so the filter has to append the
+-- untagged tail itself or the check for it fails.
+local function lex_short(self, text)
+	if #text < 5 then
+		return {}
+	end
+	return { "keyword", 5 }
+end
+
+local function lex_raise(self, text)
+	error("this lexer always raises")
+end
+
+local lexers = {
+	fake = { lex = lex_words },
+	short = { lex = lex_short },
+	badlex = { lex = lex_raise },
+}
+
+function M.load(name)
+	local lexer = lexers[name]
+	if lexer == nil then
+		error("no fake lexer named " .. tostring(name))
+	end
+	return lexer
+end
+
+function M.detect(filename)
+	if filename:match("%.viadetect$") then
+		return "fake"
+	end
+	return nil
+end
+
+return M