Deprecation in Parrot

This is a list of currently deprecated features of Parrot. Every deprecation should have an associated RT ticket, but this is not the case yet [RT#41226].

new object system

The object system of Parrot is being overhauled. This touches some opcode and PIR syntax. So some deprecation can be found in pdd17_pmc.pod.

.imc file extension

http://xrl.us/jc4u

 IMC vs. PIR
 Two names enter
 One name leaves

 /me giggles
 -- Chip Salzenberg

Deprecated C APIs

Currently no C APIs are deprecated.

Deprecated methods

PGE

PGE::P6Regex is now a registered compiler, and should be used like so:

 <@pmichaud> it's easy; instead of  $P0 = find_global "PGE", "p6rule"
   one now does  $P0 = compreg "PGE::P6Regex"

This syntax is also true for PGE::Glob and PGE::P5Regex

Deprecated ops

From http://www.parrotcode.org/docs/ops/var.html, the following ops are deprecated:

store_global

find_global

find_name

There are several variants of some of the above ops; all are deprecated, and are replaced by the ops {set,get}_[hll,root]_global. See also http://www.parrotcode.org/docs/ops/var.html.

substr_r

For now this op will stay available as an experimental op [RT#41749].

From http://www.parrotcode.org/docs/ops/experimental.html, the following ops are deprecated:

new(out PMC, in INT, in STR)

instantiate(out PMC)

They will be removed in the 0.5.0 release.

Deprecated Class Features

1. Type IDs will go away in 0.5.0.

2. The classname op is deprecated and will be removed in the 0.5.0 release. It's an exact duplicate of the string return variant of the typeof op.

3. The experimental instantiate opcode is deprecated and will be removed in the 0.5.0 release.

   (The instantiate vtable function becomes core in 0.5.0, but is accessed via the "new" opcode for the PMCs that use it.)

4.   PMC* subclass(PMC *name)

   The subclass vtable method is deprecated and will be removed in the 0.5.0 release.

5. The PMC union struct is deprecated and will be removed once all core PMCs have been updated.

deprecated PIR syntax

type names

As of Parrot 0.4.16 all type names for .local other than string, num, int, and pmc are deprecated. Using float for num or a basic PMC name like Array for pmc will no longer be possible in Parrot 0.4.17. [RT#42769].

method vs :method sub flag

Currently a sub can be tagged as a method using the method keyword, besides the more consistent :method. IMCC currently supports both, but will be updated to only accept :method. [RT#45399].

.pcc_begin/end_return/yield made stricter

Currently you can write:

 .pcc_begin_return
 .return 1
 .return 2
 .pcc_end_yield

It is not very clear whether this is a return or yield block. It's also possible to start a block with .pcc_begin_yield and end with .pcc_end_return. IMCC will be made more stricter, to only allow proper pairs: begin/end should match. [RT#45411].

.global directive

Although the .global directive was never implemented, this directive will be removed. [RT#45407].

.pcc_sub in PIR mode

IMCC allows for defining a sub using both the .pcc_sub and .sub keyword. In earlier days there was a semantic difference between the two, but not anymore. Therefore, the .pcc_sub directive is removed from PIR mode. It will still be possible to use it in PASM mode. [RT#45409].

Deprecated compiler tools

Currently no compiler tools are deprecated.

FUTURE changes

Not yet deprecated, but it's recommended to use the new syntax and gradually change the old.

PMC Class name IDs

Instead of:

  $P0 = new Integer

or

  $P0 = new .Integer # better, but ...

we are moving to use:

  $P0 = new 'Integer'

Assignment syntax with opcodes [RT#36283]

When the first argument of an opcode is OUT, then the assignment syntax will be allowed, as it is today.

In any other case (i.e. INOUT, IN), this will become a syntax error. For example:

    $S0 = print
    $P0 = substr 1, 2, "x"

Will have to be:

    print $S0
    substr $P0, 1, 2, "x"