porom/lib/babycode.lua

54 lines
1.8 KiB
Lua

local babycode = {}
---renders babycode to html
---@param s string input babycode
---@param escape_html fun(s: string): string function that escapes html
function babycode.to_html(s, escape_html)
if not s or s == "" then return "" end
-- extract code blocks first and store them as placeholders
-- don't want to process bbcode embedded into a code block
local code_blocks = {}
local code_count = 0
local text = s:gsub("%[code%](.-)%[/code%]", function(code)
code_count = code_count + 1
-- strip leading and trailing newlines, preserve others
code_blocks[code_count] = code:gsub("^%s*(.-)%s*$", "%1")
return "\1CODE:"..code_count.."\1"
end)
-- replace `[url=https://example.com]Example[/url] tags
text = text:gsub("%[url=([^%]]+)%](.-)%[/url%]", function(url, label)
return '<a href="'..escape_html(url)..'">'..escape_html(label)..'</a>'
end)
-- replace `[url]https://example.com[/url] tags
text = text:gsub("%[url%]([^%]]+)%[/url%]", function(url)
return '<a href="'..escape_html(url)..'">'..escape_html(url)..'</a>'
end)
-- bold, italics, strikethrough
text = text:gsub("%[b%](.-)%[/b%]", "<strong>%1</strong>")
text = text:gsub("%[i%](.-)%[/i%]", "<em>%1</em>")
text = text:gsub("%[s%](.-)%[/s%]", "<del>%1</del>")
-- replace loose links
text = text:gsub("(https?://[%w-_%.%?%.:/%+=&~%@#%%]+[%w-/])", function(url)
if not text:find('<a[^>]*>'..url..'</a>') then
return '<a href="'..escape_html(url)..'">'..escape_html(url)..'</a>'
end
return url
end)
-- normalize newlines, replace them with <br>
text = text:gsub("\r?\n\r?\n+", "<br>"):gsub("\r?\n", "<br>")
-- replace code block placeholders back with their original contents
text = text:gsub("\1CODE:(%d+)\1", function(n)
return "<pre><code>"..code_blocks[tonumber(n)].."</code></pre>"
end)
return text
end
return babycode