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.\" ========================================================================
.\"
.IX Title "Call::Context 3pm"
.TH Call::Context 3pm "2022-10-13" "perl v5.34.0" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.SH "NAME"
Call::Context \- Sanity\-check calling context
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\&    use Call::Context;
\&
\&    sub gives_a_list {
\&
\&        #Will die() if the context is not list.
\&        Call::Context::must_be_list();
\&
\&        return (1, 2, 3);
\&    }
\&
\&    gives_a_list();             # die()s: incorrect context (void)
\&
\&    my $v = gives_a_list();     # die()s: incorrect context (scalar)
\&
\&    my @list = gives_a_list();  # lives
\&
\&    #\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-
\&
\&    sub scalar_is_bad {
\&
\&        #Will die() if the context is not list.
\&        Call::Context::must_not_be_scalar();
\&
\&        return (1, 2, 3);
\&    }
\&
\&    scalar_is_bad();            # lives
\&
\&    my $v = scalar_is_bad();    # die()s: incorrect context (scalar)
\&
\&    my @list = scalar_is_bad(); # lives
.Ve
.SH "DISCUSSION"
.IX Header "DISCUSSION"
If your function only expects to return a list, then a call in some other
context is, by definition, an error. The problem is that, depending on how
the function is written, it may actually do something expected in testing, but
then in production act differently.
.SH "FUNCTIONS"
.IX Header "FUNCTIONS"
.SS "\fBmust_be_list()\fP"
.IX Subsection "must_be_list()"
\&\f(CW\*(C`die()\*(C'\fRs if the calling function is itself called outside list context.
(See the \s-1SYNOPSIS\s0 for examples.)
.SS "\fBmust_not_be_scalar()\fP"
.IX Subsection "must_not_be_scalar()"
\&\f(CW\*(C`die()\*(C'\fRs if the calling function is itself called in scalar context.
(See the \s-1SYNOPSIS\s0 for examples.)
.SH "EXCEPTIONS"
.IX Header "EXCEPTIONS"
This module throws instances of \f(CW\*(C`Call::Context::X\*(C'\fR. \f(CW\*(C`Call::Context::X\*(C'\fR is
overloaded to stringify; however, to keep memory usage low, \f(CW\*(C`overload\*(C'\fR is not
loaded until instantiation.
.SH "REPOSITORY"
.IX Header "REPOSITORY"
https://github.com/FGasper/p5\-Call\-Context