siiky
2022/07/05
2022/07/05
en
Yesterday I made a Scheme library to read Gemtext into a simple AST: a list of lines of text, headers, links, list blocks, or code blocks.
Text
Just a string, not tagged in any way. Empty lines are kept.
`(header ,(string-length $1) ,$2)
If *strict-gemtext-headers* is enabled, header lines of level > 3 are not considered headers.
"##### title" ; (w/ *strict-gemtext-headers* enabled)
'(header 5 "title") ; (w/ *strict-gemtext-headers* disabled)
Links
=> some-uri.gmi Optional alt text
'(link "some-uri.gmi" "Optional alt text")
If there's no alt text, the empty string is used:
'(link "some-uri.gmi" "")
Lists
'(list "item 1"
"item 2")
Code blocks
(pretend there's no space between the three backticks)
`` `some optional alt text
some
pre-formatted
text
`` `
'(code "some optional alt text"
"some"
"pre-formatted"
"text")
If there's no alt text, the empty string is used:
`` `some optional alt text
some
pre-formatted
text
`` `
'(code ""
"some"
"pre-formatted"
"text")
Example
# Factorial
There are two steps to compute the factorial of a number:
* Compute the list of integers from 1 up to the number
* Multiply all the integers of the list
=> gemini://gemi.dev/cgi-bin/wp.cgi/view/en?Factorial
=> gemini://gemi.dev/cgi-bin/wp.cgi/view/en?Factorial Factorial
## Haskell code
Here's the code in Haskell:
`` `hs
fact n = prod [1..n]
`` `
'((header 1 "Factorial")
""
"There are two steps to compute the factorial of a number:"
""
(list "Compute the list of integers from 1 up to the number"
"Multiply all the integers of the list")
""
(link "gemini://gemi.dev/cgi-bin/wp.cgi/view/en?Factorial" "")
(link "gemini://gemi.dev/cgi-bin/wp.cgi/view/en?Factorial" "Factorial")
""
(header 2 "Haskell code")
""
"Here's the code in Haskell:"
""
(code "hs"
"fact n = prod [1..n]"))
Output Patterns
(header level title)
(link uri alt-text)
(code alt-text . lines)
(list . items)