@@code.k
  @hpos_args :hpos left @
  @caption_args :caption_side top @
  | text.literal :
A block of code, given here and displayed uninterpreted.  Code that lives in a
file is ^@source_listing instead; ^@code is only for a block written inline.

It carried ":filename" and ":pattern" until 2026-08-16.  Neither was ever
implemented -- "filename" is read only by ^@source_listing and "pattern" by
nothing at all -- and because a literal parameter's content begins at the first
katom when no bar is written, "^@code :filename f :pattern p" DISPLAYED THOSE
WORDS as the listing rather than acting on them.
@@

@@code.html,tex :: @eval code_block.Code(K) @ @@

@@c.k code_text.literal :
A word or phrase displayed verbatim in a line.  Like ^@code, its content is
LITERAL -- nothing in it is interpreted as Klammertext -- so it must be closed
with the named delimiter "c^@".  ^@c is the in-line form and ^@code the block
form of the same thing; before 2026-08-16 this parameter was an ordinary
string, so a "^#" or a bare "^@" inside it was read as Klammertext and usually
failed the file, which is not what "verbatim" can mean.
@@

@@c.html,tex :: @eval code_block.Code_fragment(K) eval@
@@

# :cwd makes the filename resolve against the DOCUMENT's directory, not
# the directory ktext happens to run in.
@@source_listing.k filename :marker
  @hpos_args :hpos left @
  @caption_args :caption_side top @
  : Code read from a file and displayed uninterpreted.  *filename* is the file;
without ":marker" the whole file is listed.

":marker P" lists only the region BETWEEN two lines that consist solely of
"//P" and begin in the first column.  The source file therefore declares its
own extractable regions and the document asks for one by name, so the two
cannot drift apart silently: renaming or reformatting the code does not change
what is extracted, and a region that disappears is an error rather than a
quietly different listing.

Named "^@source_file" until 2026-08-16.  # retired-ok
@@
@@source_listing.html,tex :: @eval :cwd *K_input_dir* code_block.Source(K) @ @@