When reading from stdin, bat should use --file-name (if present) to pick the syntax highlighter

[anntzer]

Per discussion at #237 (comment).

When reading from stdin, bat can't perform highlighting as it doesn't know the filename... unless it is given with --file-name. (We could even always use --file-name (if present) to pick the syntax even if the real filename is available, but that may run into issues if that name is inconsistent with the real name.)

[neuronull]

I would like to implement this.

[sharkdp]

Thank you for your request.

When reading from stdin, bat can't perform highlighting as it doesn't know the filename... unless it is given with --file-name.

That's not quite correct. bat can also perform syntax detection by reading the first line. This also works for input coming from stdin, for example

echo "<?php\nprint 'hi';?>" | bat # highlighted as PHP
echo "#\!/bin/bash\necho hi" | bat # highlighted as Bash

We should make sure that this still works.

For normal input from files, the filename has precedence. This means that a file named test.cpp will always be highlighted as C++, even if the first line would indicate, that it is something else. I'm actually not sure if that behavior should be changed?

We could even always use --file-name (if present) to pick the syntax even if the real filename is available, but that may run into issues if that name is inconsistent with the real name.

Yes, that should be discussed first.

I would like to implement this.

Sounds great! 👍

[neuronull]

For normal input from files, the filename has precedence. This means that a file named test.cpp will always be highlighted as C++, even if the first line would indicate, that it is something else. I'm actually not sure if that behavior should be changed?

From what I saw experimentally, there seem to be limits to the first-line detection. IMHO it makes sense to prioritize the filename/extension.