zettelkasten.nvim/lua/zettelkasten/link.lua
Marty Oehme 2a3e213ac8
Move link extraction to link module
Both link creation and extraction, all derived from parser
functionality, should run within the link module and actions should only
make use of it to invoke editor functionality.
2020-11-04 22:04:31 +01:00

127 lines
3.8 KiB
Lua

local L = {}
local o = require 'zettelkasten.options'
local a = require 'zettelkasten.anchor'
local parsers = {
markdown = {
ref = "%[.-%]%((.-)%)",
text = "%[(.-)%]%(.-%)",
style_func = function(link, text, extension)
return "[" .. L.trimmed(text) .. "](" .. link .. extension .. ")"
end
},
wiki = {
ref = "%[%[(.-)|?.-%]%]",
text = "%[%[.-|?(.-)%]%]",
style_func = function(link, text)
local pipe = ""
text = L.trimmed(text)
if text and text ~= "" then pipe = "|" .. text end
return "[[" .. link .. pipe .. "]]"
end
}
}
-- Returns the text cleaned up to be more useful in a link.
-- Spaces are replaced by dashes and everything is lowercased.
function L.urlify(text)
text = text or ""
return text:lower():gsub(" ", "-")
end
-- Returns the untouched text with the extension set in options appended
-- at the end.
function L.append_extension(text) return text .. o.zettel().extension end
local function must_have(content)
if not content or content == "" then
error("Link is not allowed to be empty.")
end
end
-- Returns text with surrounding whitespace trimmed. Returns empty string
-- if only whitespace.
function L.trimmed(text)
if not text then return end
return text:match '^()%s*$' and '' or text:match '^%s*(.*%S)'
end
-- Returns a markdown-compatible transformation of the link and text combination
-- passed in.
function L.style_markdown(link, text)
must_have(link)
return "[" .. L.trimmed(text) .. "](" .. link .. ")"
end
-- Returns a wikilink-compatible transformation of the link and text combination
-- passed in, adding the text as a pipe if it exists.
function L.style_wiki(link, text)
must_have(link)
local pipe = ""
text = L.trimmed(text)
if text and text ~= "" then pipe = "|" .. text end
return "[[" .. link .. pipe .. "]]"
end
-- Returns a correctly formatted link to a zettel.
-- Requires an anchor to be passed in.
-- Takes an optional link text which will be added to the link.
-- Takes an optional style according to which the link will be transformed.
function L.create(anchor, text, style)
style = style or o.zettel().link_style
if style == "markdown" then
local link = (a.prepend(anchor, L.urlify(L.trimmed(text))))
return parsers.markdown.style_func(link, text, o.zettel().extension)
elseif style == "wiki" then
return parsers.wiki.style_func(anchor, text)
end
error("Link creation failed.")
end
-- Returns a correctly formatted link to a new zettel (without anchor).
-- Takes an optional link text which will be added to the link.
-- Takes an optional style according to which the link will be transformed.
function L.new(text, style)
local anchor = a.create()
return L.create(anchor, text, style)
end
-- Return all links contained in the input given in an array.
-- Returned link tables have the following structure:
-- link = { text=, ref=, startpos=27, endpos=65 }
function L.extract_all(input)
if not input then return end
local links = {}
local curpos = 1
for _, parser in pairs(parsers) do
while input:find(parser.ref, curpos) do
local ref = input:match(parser.ref, curpos)
local text = input:match(parser.text, curpos)
local startpos, endpos = input:find(parser.ref, curpos)
table.insert(links, {
ref = ref,
text = text,
startpos = startpos,
endpos = endpos
})
curpos = endpos
end
end
return links
end
return {
new = L.new,
create = L.create,
style_wiki = L.style_wiki,
style_markdown = L.style_markdown,
append_extension = L.append_extension,
urlify = L.urlify,
extract_all = L.extract_all
}