parrot calling conventions state table

this document expresses the calling conventions as outlined in PDD03 in table format. this is a work in progress, which, when finished, should assist in creating an exhaustive test suite for calling conventions.

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          |                          DEST                         |      |
          |          unnamed          |           named         *3|      |
          |   required  |   optional  |   required  |   optional  |      |
          |      |    *1|      |    *1|      |    *1|      |    *1|      |
          | nrml | slrp | nrml | slrp | nrml | slrp | nrml | slrp | END  |
  ------------------------------------------------------------------------
          |      |      |      |      |      |      |      |      |      |
A    nrml |  P1  |  P2  |  P1  |  P2  |  E6  |  E6  |  E6  |  E6  |  E1  |
   u      |      |      |      |      |      |      |      |      |      |
   n----------------------------------------------------------------------
   n  *1,2|      |      |      |      |      |      |      |      |      |
B  a flat |  P3  |  P3  |  P3  |  P3  |  P4  |  P5  | P4   |  P5  |  E2  |
   m      |      |      |      |      |      |      |      |      |      |
   e----------------------------------------------------------------------
   d    *1|      |      |      |      |      |      |      |      |      |
C    mayb |  P1  |  X1  |  P1  |  X1  |      |      |      |      |  E2  |
  S       |      |      |      |      |      |      |      |      |      |
  R-----------------------------------------------------------------------
  C       |      |      |      |      |      |      |      |      |      |
D    nrml |  E5  |  E5  |  E5  |  E5  |      |      |      |      |  E1  |
          |      |      |      |      |      |      |      |      |      |
   n----------------------------------------------------------------------
   a    *3|      |      |      |      |      |      |      |      |      |
E  m flat |  E5  |  E5  |  E5  |  E5  |      |      |      |      |  E2  |
   e      |      |      |      |      |      |      |      |      |      |
   d----------------------------------------------------------------------
          |      |      |      |      |      |      |      |      |      |
F    mayb |  E4  |  E4  |  E4  |  E4  |  E4  |  E4  |  E4  |  E4  |  E2  |
          |      |      |      |      |      |      |      |      |      |
  ------------------------------------------------------------------------
          |      |      |      |      |      |      |      |      |      |
G     END |  E3  |  E3  |  D1  |  D1  |  E3  |  E3  |  D1  |  D1  |  D1  |
          |      |      |      |      |      |      |      |      |      |
  ------------------------------------------------------------------------

Glossary

Flag Values

nrml  no flags   (src: val & 0x03a0 = 0; dest: val & 0x0260 = 0)
slrp  SLURPY     (val & 0x0020 = 1)
flat  FLAT       (val & 0x0020 = 1)

Passing

P1  pass as-is, next state
P2  pass as-is, next src
P3  pass contents as array items, next
P4  pass current array item as-is, next src array item
P5  pass current array items as pairs (a[0],a[0]) or as (a[0],a[1]) (a.size % 2 = 0)
P4  pass current array item as-is, next src array item
P5  pass current array items as pairs (a[0],a[0]) or as (a[0],a[1]) (a.size % 2 = 0)

Expressions

X1  if(src pmc is aggregate or reference to aggregate)
      if dest is array, pass as flat
      if dest is hash, pass as pairs

Errors

E1  overflow
E2  overflow if aggregate is not empty
E3  underflow
E4  [removed]
E5  named parameter passed, unnamed expected
E6  unnamed parameter passed, named expected

Done

D1  done

Notes

*1  pmc only
*2  error unless pmc is aggregate or reference to aggregate
*3  pmc or string constant only

Examples

A:5 'caller'(1, 2) # caller .param pmc two :named('two') ; .param pmc one :named('one') two = 1 ; one = 2