Latest version(s) of MPP print locations when using foreign code blocks, and it makes it easier to track errors. But the locations disappear after the foreign code has been evaluated. Evaluation of the foreign code should print source locations. However it's not as trivial as saying it: the format of the location depends on the final language, not the 1st nor the 2nd. But, it should be not too hard to make a version that works with CPP locations. This will probably bump MPP version to 0.2.x. as it will need a few changes in the interface.

It seems src/lib is unnecessary and misnamed. The library is actually all directly under src.

When mpp is used in scripts, it is not always clear what the origin of an error is. Thus MPP should identify itself in error messages.

It happens sometimes with mpp.0.1.0.

Generating

"foo
#42 "bar.ml"
baz"

is not helpful...

Well, it's easier said than done.

Perhaps just allow the use of different foreign languages with possibility to set a target language for each of them. It'd certainly be less twisted...

elseifdef doesn't work. https://github.com/ocaml/MPP-language-blender/blame/master/README.md#L21 says it exists but https://github.com/ocaml/MPP-language-blender/blob/master/src/mpp_actions.ml#L341 seems to have it disabled.

I want to do:

mpp -set x=true foo.mpp
mpp -set x=false foo.mpp

and then in foo.mpp, do something like

{{if (( get x )) = true
  Got true.
}}
{{if (( get x )) = false
  Got false.
}}

Is there some way to do the above?

Currently in Opam it says:

depends      "ocaml" {>= "4.03" & < "5.0.0"} "dune" {> "1.11.0"} "stdlib-shims"

At the minimum, we need the following:

• Each module should have a high level description of what the module is about.
• Each function and type should be described.

Thanks! This would make it much easier to use MPP.

From the root of the ocaml.org repository, the following command

mpp -so '((!' -sc '!))' -son '{{!' -scn '!}}' -soc '' -scc '' -sec '' -sos '{{<' -scs '>}}' -its template/main.mpp -o /tmp/c.html -set "filename=x" -set "page=/tmp/preprocessed_99problems.html"

terminates with the exception Stack_overflow where /tmp/preprocessed_99problems.html is the result of processing the file site/learn/tutorials/99problems.md with omd.

{{! ifdef foo something !}}
{{! else
  something else
!}}

is invalid because the else command is lexed as "else\n". it seems newline is a valid character in an indentifier and does not count as whitespace. This isn't intuitive.

Sometimes (not always) MPP dies on errors and errors messages are mute, well they shouldn't be. ==> let error messages be!

and is necessary for pinning

(I'm simply copy-pasting the content of the file ideas_draft.md as I'm in the process of cleaning the repo)

Currently, what is between the opening token and the first following
space is the name of the block. I'm wondering how bad it would be, in
order to avoid that "mandatory space", to consider that names can't be
builtin names. That would allow the space to be optional.

In this context, it would mean that builtin names are sort of keywords...

Is there a library function corresponding to the main app's functionality? As far as I can tell, it is within mpp_main.ml but not exposed as a callable function. I would like to have the main functionality available with strings as the input/output, rather than files. This would allow more efficient processing in external scripts and avoid having to make messy system calls.

The bash language output uses echo, so it adds new-lines.

{
cat <<EOF
hello {< printf "world" >}!
EOF
} | mpp -l bash | bash

gives

hello 
world!

Instead of echo ... it could use printf '%s' ... (it's POSIX sh).

Consider you have a file in a directory called src/ with the following contents:

$ cat src/foo.mpp
(( input bar.txt ))

Currently, the file bar.txt is searched relative to the current working directory of whatever process you're calling mpp from. I think it would be more intuitive if the path was interpreted as relative to src/, i.e. the directory in which the mpp file resides.

One issue with this is related to my request in #7 for a library function corresponding to the command line app. If you provide a function val mpp_on_string : string -> string, which directly operates on a string, then you don't have a file path to get the parent directory from. A solution could be to have such a function also take an optional filename argument. If this argument is not provided, then you fallback to using the current working directory.

If I run

mpp -so '((!' -sc '!))' -son '{{!' -scn '!}}' -soc '' -scc '' -sec '' -sos '{{<' -scs '>}}' -its  -set "filename=site/index.md" -set "page=ocaml.org/index.html.tmp" tpl/main.mpp -o "ocaml.org/index.html" 

in a terminal, I get

sh: 1: Syntax error: redirection unexpected

The strings are properly escaped. Is it possible that the problem comes from mpp trying to execute commands and not escaping properly the arguments? (No time to investigate right now)

I broke the compatibility with ocaml < 4.02.0

I'll fix that... hopefully for version 0.2.1