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warnings, caller, wantarray, ref, $#_
Miscellany example from a Well House Consultants training course
More on Miscellany [link]
Source code: waw Module: P303
# warnings, caller, wantarray, ref, $#_
{ package eggs; sub yolk () { # () says MUST not have any params passed in @stuff = (5,8,7,6); $thing = 77; %what = (17,65,44,33); $x = demo(16,77); print ("$x \n"); @y = demo("hello"); print ("@y \n"); print (demo(\@stuff),"\n"); print (scalar(demo(\$thing)),"\n"); print (demo(\%what),"\n"); } sub demo { my ($p) = @_; print ("\n\nthis is a ",ref($p)," with ",$#_+1," params\n"); $silly = 16; my ($q,$r,$s) = caller(); print ("I am called from package $q program file $r line $s\n"); no warnings; my ($q,$r,$s) = caller(1); # (And more fields are available - RTFM) use warnings; print ("That was called from package $q program file $r line $s\n"); $stupid = "git"; if (wantarray) { return (2,4,6,8); } else { return "milkbottle"; } } } # end of package eggs::yolk(); # eggs::yolk("yellow"); # Commented out. Would give error at prototype __END__ wizard:course graham$ perl waw Name "eggs::stupid" used only once: possible typo at waw line 35. this is a with 2 params I am called from package eggs program file waw line 13 That was called from package main program file waw line 46 milkbottle this is a with 1 params I am called from package eggs program file waw line 15 That was called from package main program file waw line 46 2 4 6 8 this is a ARRAY with 1 params I am called from package eggs program file waw line 17 That was called from package main program file waw line 46 2468 this is a SCALAR with 1 params I am called from package eggs program file waw line 18 That was called from package main program file waw line 46 milkbottle this is a HASH with 1 params I am called from package eggs program file waw line 19 That was called from package main program file waw line 46 2468 wizard:course graham$ Learn about this subject
This module and example are covered on our public Perl for Larger Projects course. If you have a group of
three or more trainees who need to learn the subject, we can also arrange a
private or on site course for you.
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Other Examples
This example comes from our "Miscellany" training module. You'll find a description of the topic and some
other closely related examples on the "Miscellany" module index page.
Full description of the source code
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