Implementing a function in a macro?

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1

Hi all,

Is it possible to define a macro that implements another function? I’m trying to write a macro that lets you define a “main” function that takes argc and argv as expected, but also takes views for things like “you have a readable file descriptor at int 0” and “errno is unset” to represent “global” process state that can be changed and tracked linearly. Currently, I have this, which is failing to compile:

(* Set a given function to be the POSIX entry point

  • This is equivalent to implementing main as the passed in function,
  • except that in addition to argc and argv views corresponding to initial
  • global program state in the POSIX environment are passed.
  • Currently, an errno_v ( free ) proof is passed. In the future, proofs
  • corresponding to open file descriptors for stdin, stdout, and stderr will
  • be passed as well
    *)
    macdef set_posix_entrypoint ( func ) =
    implement main ( argc, argv ) = let
    extern praxi { v: view } __assert_view (): v
    prval ev = __assert_view < errno_v ( free ) > ()
    val res = ,(func) ( ev | argc, argv )
    extern praxi { v: view } __unassert_view ( x: v ): ()
    prval () = __unassert_view ( ev )
    in res end

I get many errors, but the first one is:

481(line=12, offs=3) – 490(line=12, offs=12): error(parsing): the syntactic entity [d0exp] is needed.

(the line and offsets refer to the word “implement” above). It’s unclear to me how to continue, sorry for my ignorance!

Thanks,
Shea

2

Ah ha, I see, thank you.> On Mar 12, 2015, at 12:17 PM, gmhwxi gmh...@gmail.com wrote:

macdef expects a dynamic expression on the right-hand side of ‘=’;
‘implement’ introduces a declaration. So there is a mismatch here.

Anyways, I feel that ‘macdef’ is not really meant for this kind of heavy lifting.
Maybe you could implement set_posix_entrypoint in PHP.

On Thursday, March 12, 2015 at 11:03:25 AM UTC-4, Shea Levy wrote:
Hi all,

Is it possible to define a macro that implements another function? I’m trying to write a macro that lets you define a “main” function that takes argc and argv as expected, but also takes views for things like “you have a readable file descriptor at int 0” and “errno is unset” to represent “global” process state that can be changed and tracked linearly. Currently, I have this, which is failing to compile:

(* Set a given function to be the POSIX entry point
*

  • This is equivalent to implementing main as the passed in function,
  • except that in addition to argc and argv views corresponding to initial
  • global program state in the POSIX environment are passed.
  • Currently, an errno_v ( free ) proof is passed. In the future, proofs
  • corresponding to open file descriptors for stdin, stdout, and stderr will
  • be passed as well
    *)
    macdef set_posix_entrypoint ( func ) =
    implement main ( argc, argv ) = let
    extern praxi { v: view } __assert_view (): v
    prval ev = __assert_view < errno_v ( free ) > ()
    val res = ,(func) ( ev | argc, argv )
    extern praxi { v: view } __unassert_view ( x: v ): ()
    prval () = __unassert_view ( ev )
    in res end

I get many errors, but the first one is:

481(line=12, offs=3) – 490(line=12, offs=12): error(parsing): the syntactic entity [d0exp] is needed.

(the line and offsets refer to the word “implement” above). It’s unclear to me how to continue, sorry for my ignorance!

Thanks,
Shea

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3

macdef expects a dynamic expression on the right-hand side of ‘=’;
‘implement’ introduces a declaration. So there is a mismatch here.

Anyways, I feel that ‘macdef’ is not really meant for this kind of heavy
lifting.
Maybe you could implement set_posix_entrypoint in PHP.On Thursday, March 12, 2015 at 11:03:25 AM UTC-4, Shea Levy wrote:

Hi all,

Is it possible to define a macro that implements another function? I’m
trying to write a macro that lets you define a “main” function that takes
argc and argv as expected, but also takes views for things like “you have a
readable file descriptor at int 0” and “errno is unset” to represent
“global” process state that can be changed and tracked linearly. Currently,
I have this, which is failing to compile:

(* Set a given function to be the POSIX entry point
*

  • This is equivalent to implementing main as the passed in function,
  • except that in addition to argc and argv views corresponding to initial
  • global program state in the POSIX environment are passed.
  • Currently, an errno_v ( free ) proof is passed. In the future, proofs
  • corresponding to open file descriptors for stdin, stdout, and stderr
    will
  • be passed as well
    *)
    macdef set_posix_entrypoint ( func ) =
    implement main ( argc, argv ) = let
    extern praxi { v: view } __assert_view (): v
    prval ev = __assert_view < errno_v ( free ) > ()
    val res = ,(func) ( ev | argc, argv )
    extern praxi { v: view } __unassert_view ( x: v ): ()
    prval () = __unassert_view ( ev )
    in res end

I get many errors, but the first one is:

481(line=12, offs=3) – 490(line=12, offs=12): error(parsing): the
syntactic entity [d0exp] is needed.

(the line and offsets refer to the word “implement” above). It’s unclear
to me how to continue, sorry for my ignorance!

Thanks,
Shea