Transcribe

Transcribe is a simple program which generates Markdown documentation from code
comments.

The general idea is that each "export" should be accompanied by a "docstring".
The first line of the "docstring" should be a Haskell-inspired type signature
in the form :: .

``javascript
//# map :: (a -> b) -> Array a -> Array b
//.
//. Transforms a list of elements of type a into a list of elements
//. of type b using the provided function of type a -> b.
//.
//. `javascript
//. > map (String) ([1, 2, 3, 4, 5])
//. ['1', '2', '3', '4', '5']
//. `
function map(f) {
return function(xs) {
var output = [];
for (var idx = 0; idx < xs.length; idx += 1) {
output.push (f (xs[idx]));
}
return output;
};
}
`

The __--heading-prefix__ option specifies which lines in the source files
contain type signatures to become headings in the output. The default value
is //#; specify a different value if using a different comment style. For
example:

--heading-prefix '#%'

The __--prefix__ option specifies which lines in the source files should
appear in the output along with the lines prefixed with .
The default value is //.; specify a different value if using a different
comment style. For example:

--prefix '#.'

Each line beginning with zero or more whitespace characters followed by the
prefix is included in the output, sans prefix and leading whitespace. The .
in the default prefix makes it possible to be selective about which comments
are included in the output: comments such as // Should never get here! will
be ignored.

The __--url__ option specifies a template for generating links to specific
lines of source code on GitHub or another code-hosting site. The value should
include {filename} and {line} placeholders to be replaced with the filename
and line number of each of the signature lines. For example:

--url 'https://github.com/plaid/sanctuary/blob/v0.4.0/{filename}#L{line}'

Avoid pointing to a moving target: include a tag name or commit hash rather
than a branch name such as master.

The __--heading-level__ option specifies the heading level, an integer in
range \[1, 6\]. The default value is 3, which corresponds to an

element in HTML. Specify a different value if desired. For example:

--heading-level 4

The __--insert-into__ option specifies the name of a file into which
Transcribe will insert the generated output. By default, Transcribe writes to
stdout. However, if --insert-into is provided, Transcribe will insert the
output in the specified file between two special tags: and
. For example:

--insert-into README.md

The options should be followed by one or more filenames. The filenames may
be separated from the options by --. Files are processed in the order in
which they are specified.

Here's a complete example:

$ transcribe \
> --url 'https://github.com/plaid/example/blob/v1.2.3/{filename}#L{line}' \
> -- examples/fp.js
### map :: (a -⁠> b) -⁠> Array a -⁠> Array b

Transforms a list of elements of type a into a list of elements
of type b using the provided function of type a -> b.

`javascript
> map (String) ([1, 2, 3, 4, 5])
['1', '2', '3', '4', '5']
`

### filter :: (a -⁠> Boolean) -⁠> Array a -⁠> Array a

Returns the list of elements which satisfy the provided predicate.

`javascript
> filter (function(n) { return n % 2 === 0; }) ([1, 2, 3, 4, 5])
[2, 4]
`

By default, the output is written to stdout. One could redirect it to a file to
generate lightweight API documentation:

$ printf '\n## API\n\n' >>README.md
$ transcribe \
> --url 'https://github.com/plaid/example/blob/v1.2.3/{filename}#L{line}' \
> -- examples/fp.js >>README.md

Reading from stdin is not currently supported.

One could also insert the output into an existing file by providing the
--insert-into` option:

$ transcribe \
> --url 'https://github.com/plaid/example/blob/v1.2.3/{filename}#L{line}' \
> --insert-into README.md
> -- examples/fp.js