J3/14-204
To:       J3
From:     Robert Corbett
Subject:  Enhance CMPLX
Date: 2014 June 25

Status:  For consideration
Basic Functionality:  Enhance CMPLX

Rationale:
Users have complained that KIND= is required for the actual
argument corresponding to the dummy argument KIND in a
reference of the intrinsic function CMPLX when the
actual argument corresponding to the dummy argument X is of
type complex.  The requirement is not necessary for
resolving the reference.

Specification:
Split the template for the intrinsic function CMPLX into two
templates:  one where the argument X is of type complex, and
a second where the argument X is of type real or integer or
is a <box-literal-constant>.  The template where the
argument X is of type complex omits the dummy argument Y.
As a consequence, the requirement that no actual argument
shall correspond to Y if the argument X is of type complex
is not needed.

Syntax:
Replace the subclause header

     <<CMPLX(X [, Y, KIND])>>

with

     <<CMPLX(X [, KIND]) or CMPLX(X [, Y, KIND])>>

Edits:
[Introduction, p2, editor's choice] Add
  "In a reference of the intrinsic function CMPLX with an
   actual argument of type complex, KIND= is not needed
   to specify a KIND argument."

[339:8] (13.7.36) Replace
  "<<CMPLX(X [,Y ,KIND])>>"
with
  "<<CMPLX(X [, KIND]) or CMPLX(X [, Y, KIND])>>"

[339:11-15] Replace
  "<<Arguments.>> ... integer constant expression."
with
  "<<Arguments for CMPLX(X [, KIND]).>>
  X       shall be of type complex.
  KIND (optional) shall be a scalar integer constant
           expression.

  <<Arguments for CMPLX(X [, Y, KIND]).>>
  X       shall be of type integer or real, or a
          <boz-literal-constant>.
  Y (optional) shall be of type integer or real, or a
          <boz-literal-constant>.
  KIND (optional) shall be a scalar integer constant
          expression."

[339:18-21] Replace
  "If X is complex, ... as that of CMPLX(X, Y, KIND)"
with
  "If KIND is absent, it is as if KIND were present with
  the value KIND(0.0).  If X is complex, the result is the
  same as that of CMPLX(REAL(X), AIMAG(X), KIND).  The
  result of CMPLX(X, Y, KIND) is the complex value whose
  real part is REAL(X, KIND) and whose imaginary part is
  REAL(Y, KIND)."