package Function::Parameters;
+use v5.14.0;
+
use strict;
use warnings;
-our $VERSION = '0.03';
-
-use Devel::Declare;
-use B::Hooks::EndOfScope;
-use B::Compiling;
-
-sub guess_caller {
- my ($start) = @_;
- $start ||= 1;
+use Carp qw(confess);
- my $defcaller = (caller $start)[0];
- my $caller = $defcaller;
-
- for (my $level = $start; ; ++$level) {
- my ($pkg, $function) = (caller $level)[0, 3] or last;
- #warn "? $pkg, $function";
- $function =~ /::import\z/ or return $caller;
- $caller = $pkg;
- }
- $defcaller
+use XSLoader;
+BEGIN {
+ our $VERSION = '0.10';
+ XSLoader::load;
}
-sub _fun ($) { $_[0] }
-
-sub import {
- my $class = shift;
- my $keyword = shift;
- my $caller = guess_caller;
- #warn "caller = $caller";
-
- Devel::Declare->setup_for(
- $caller,
- { $keyword => { const => \&parser } }
- );
-
- no strict 'refs';
- *{$caller . '::' . $keyword} = \&_fun;
+sub _assert_valid_identifier {
+ my ($name, $with_dollar) = @_;
+ my $bonus = $with_dollar ? '\$' : '';
+ $name =~ /^${bonus}[^\W\d]\w*\z/
+ or confess qq{"$name" doesn't look like a valid identifier};
}
-sub report_pos {
- my ($offset, $name) = @_;
- $name ||= '';
- my $line = Devel::Declare::get_linestr();
- substr $line, $offset + 1, 0, "\x{20de}\e[m";
- substr $line, $offset, 0, "\e[31;1m";
- print STDERR "$name($offset)>> $line\n";
+sub _assert_valid_attributes {
+ my ($attrs) = @_;
+ $attrs =~ /^\s*:\s*[^\W\d]\w*\s*(?:(?:\s|:\s*)[^\W\d]\w*\s*)*(?:\(|\z)/
+ or confess qq{"$attrs" doesn't look like valid attributes};
}
-sub parser {
- my ($declarator, $start) = @_;
- my $offset = $start;
- my $line = Devel::Declare::get_linestr();
-
- my $fail = do {
- my $_file = PL_compiling->file;
- my $_line = PL_compiling->line;
- sub {
- my $n = $_line + substr($line, $start, $offset - $start) =~ tr[\n][];
- die join('', @_) . " at $_file line $n\n";
- }
- };
-
- my $atomically = sub {
- my ($pars) = @_;
- sub {
- my $tmp = $offset;
- my @ret = eval { $pars->(@_) };
- if ($@) {
- $offset = $tmp;
- die $@;
- }
- wantarray ? @ret : $ret[0]
- }
- };
-
- my $try = sub {
- my ($pars) = @_;
- my @ret = eval { $pars->() };
- if ($@) {
- return;
- }
- wantarray ? @ret : $ret[0]
- };
-
- my $skipws = sub {
- #warn ">> $line";
- my $skip = Devel::Declare::toke_skipspace($offset);
- if ($skip < 0) {
- $skip == -$offset or die "Internal error: offset=$offset, skip=$skip";
- Devel::Declare::set_linestr($line);
- return;
- }
- $line = Devel::Declare::get_linestr();
- #warn "toke_skipspace($offset) = $skip\n== $line";
- $offset += $skip;
+my @bare_arms = qw(function method);
+my %type_map = (
+ function => {
+ name => 'optional',
+ default_arguments => 1,
+ check_argument_count => 0,
+ },
+ method => {
+ name => 'optional',
+ default_arguments => 1,
+ check_argument_count => 0,
+ attrs => ':method',
+ shift => '$self',
+ invocant => 1,
+ },
+ classmethod => {
+ name => 'optional',
+ default_arguments => 1,
+ check_argument_count => 0,
+ attributes => ':method',
+ shift => '$class',
+ invocant => 1,
+ },
+);
+for my $k (keys %type_map) {
+ $type_map{$k . '_strict'} = {
+ %{$type_map{$k}},
+ check_argument_count => 1,
};
+}
- $offset += Devel::Declare::toke_move_past_token($offset);
- $skipws->();
- my $manip_start = $offset;
+sub import {
+ my $class = shift;
- my $name;
- if (my $len = Devel::Declare::toke_scan_word($offset, 1)) {
- $name = substr $line, $offset, $len;
- $offset += $len;
- $skipws->();
+ if (!@_) {
+ @_ = {
+ fun => 'function',
+ method => 'method',
+ };
+ }
+ if (@_ == 1 && $_[0] eq ':strict') {
+ @_ = {
+ fun => 'function_strict',
+ method => 'method_strict',
+ };
+ }
+ if (@_ == 1 && ref($_[0]) eq 'HASH') {
+ @_ = map [$_, $_[0]{$_}], keys %{$_[0]};
}
- my $scan_token = sub {
- my ($str) = @_;
- my $len = length $str;
- substr($line, $offset, $len) eq $str or $fail->(qq{Missing "$str"});
- $offset += $len;
- $skipws->();
- };
+ my %spec;
+
+ my $bare = 0;
+ for my $proto (@_) {
+ my $item = ref $proto
+ ? $proto
+ : [$proto, $bare_arms[$bare++] || confess(qq{Don't know what to do with "$proto"})]
+ ;
+ my ($name, $proto_type) = @$item;
+ _assert_valid_identifier $name;
+
+ unless (ref $proto_type) {
+ # use '||' instead of 'or' to preserve $proto_type in the error message
+ $proto_type = $type_map{$proto_type}
+ || confess qq["$proto_type" doesn't look like a valid type (one of ${\join ', ', sort keys %type_map})];
+ }
- my $scan_id = sub {
- my $len = Devel::Declare::toke_scan_word($offset, 0) or $fail->('Missing identifier');
- my $name = substr $line, $offset, $len;
- $offset += $len;
- $skipws->();
- $name
- };
+ my %type = %$proto_type;
+ my %clean;
- my $scan_var = $atomically->(sub {
- (my $sigil = substr($line, $offset, 1)) =~ /^[\$\@%]\z/ or $fail->('Missing [$@%]');
- $offset += 1;
- $skipws->();
- my $name = $scan_id->();
- $sigil . $name
- });
-
- my $separated_by = $atomically->(sub {
- my ($sep, $pars) = @_;
- my $len = length $sep;
- defined(my $x = $try->($pars)) or return;
- my @res = $x;
- while () {
- substr($line, $offset, $len) eq $sep or return @res;
- $offset += $len;
- $skipws->();
- push @res, $pars->();
- }
- });
-
- my $many_till = $atomically->(sub {
- my ($end, $pars) = @_;
- my $len = length $end;
- my @res;
- until (substr($line, $offset, $len) eq $end) {
- push @res, $pars->();
- }
- @res
- });
-
- my $scan_params = $atomically->(sub {
- if ($try->(sub { $scan_token->('('); 1 })) {
- my @param = $separated_by->(',', $scan_var);
- $scan_token->(')');
- return @param;
- }
- $try->($scan_var)
- });
-
- my @param = $scan_params->();
-
- my $scan_pargroup_opt = sub {
- substr($line, $offset, 1) eq '(' or return '';
- my $len = Devel::Declare::toke_scan_str($offset);
- my $res = Devel::Declare::get_lex_stuff();
- Devel::Declare::clear_lex_stuff();
- $res eq '' and $fail->(qq{Can't find ")" anywhere before EOF});
- $offset += $len;
- $skipws->();
- "($res)"
- };
+ $clean{name} = delete $type{name} || 'optional';
+ $clean{name} =~ /^(?:optional|required|prohibited)\z/
+ or confess qq["$clean{name}" doesn't look like a valid name attribute (one of optional, required, prohibited)];
- my $scan_attr = sub {
- my $name = $scan_id->();
- my $param = $scan_pargroup_opt->() || '';
- $name . $param
- };
+ $clean{shift} = delete $type{shift} || '';
+ _assert_valid_identifier $clean{shift}, 1 if $clean{shift};
- my $scan_attributes = $atomically->(sub {
- $try->(sub { $scan_token->(':'); 1 }) or return '', [];
- my $proto = $scan_pargroup_opt->();
- my @attrs = $many_till->('{', $scan_attr);
- ' ' . $proto, \@attrs
- });
+ $clean{attrs} = join ' ', map delete $type{$_} || (), qw(attributes attrs);
+ _assert_valid_attributes $clean{attrs} if $clean{attrs};
+
+ $clean{default_arguments} =
+ exists $type{default_arguments}
+ ? !!delete $type{default_arguments}
+ : 1
+ ;
+ $clean{check_argument_count} = !!delete $type{check_argument_count};
+ $clean{invocant} = !!delete $type{invocant};
- my ($proto, $attributes) = $scan_attributes->();
- my $attr = @$attributes ? ' : ' . join(' ', @$attributes) : '';
+ %type and confess "Invalid keyword property: @{[keys %type]}";
- $scan_token->('{');
+ $spec{$name} = \%clean;
+ }
+
+ for my $kw (keys %spec) {
+ my $type = $spec{$kw};
+
+ my $flags =
+ $type->{name} eq 'prohibited' ? FLAG_ANON_OK :
+ $type->{name} eq 'required' ? FLAG_NAME_OK :
+ FLAG_ANON_OK | FLAG_NAME_OK
+ ;
+ $flags |= FLAG_DEFAULT_ARGS if $type->{default_arguments};
+ $flags |= FLAG_CHECK_NARGS if $type->{check_argument_count};
+ $flags |= FLAG_INVOCANT if $type->{invocant};
+ $^H{HINTK_FLAGS_ . $kw} = $flags;
+ $^H{HINTK_SHIFT_ . $kw} = $type->{shift};
+ $^H{HINTK_ATTRS_ . $kw} = $type->{attrs};
+ $^H{+HINTK_KEYWORDS} .= "$kw ";
+ }
+}
- my $manip_end = $offset;
- my $manip_len = $manip_end - $manip_start;
- #print STDERR "($manip_start:$manip_len:$manip_end)\n";
+sub unimport {
+ my $class = shift;
- my $params = @param ? 'my (' . join(', ', @param) . ') = @_;' : '';
- #report_pos $offset;
- $proto =~ tr[\n][ ];
+ if (!@_) {
+ delete $^H{+HINTK_KEYWORDS};
+ return;
+ }
- if (defined $name) {
- my $pkg = __PACKAGE__;
- #print STDERR "($manip_start:$manip_len) [$line]\n";
- substr $line, $manip_start, $manip_len, " do { sub $name$proto; sub $name$proto$attr { BEGIN { ${pkg}::terminate_me(q[$name]); } $params ";
- } else {
- substr $line, $manip_start, $manip_len, " sub$proto$attr { $params ";
+ for my $kw (@_) {
+ $^H{+HINTK_KEYWORDS} =~ s/(?<![^ ])\Q$kw\E //g;
}
- #print STDERR ".> $line\n";
- Devel::Declare::set_linestr($line);
}
-sub terminate_me {
- my ($name) = @_;
- on_scope_end {
- my $line = Devel::Declare::get_linestr();
- #print STDERR "~~> $line\n";
- my $offset = Devel::Declare::get_linestr_offset();
- substr $line, $offset, 0, " \\&$name };";
- Devel::Declare::set_linestr($line);
- #print STDERR "??> $line\n";
- };
-}
-1
+'ok'
__END__
+=encoding UTF-8
+
=head1 NAME
Function::Parameters - subroutine definitions with parameter lists
use Function::Parameters;
+ # simple function
fun foo($bar, $baz) {
return $bar + $baz;
}
- fun mymap($fun, @args) :(&@) {
+ # function with prototype
+ fun mymap($fun, @args)
+ :(&@)
+ {
my @res;
for (@args) {
push @res, $fun->($_);
}
print "$_\n" for mymap { $_ * 2 } 1 .. 4;
+
+ # method with implicit $self
+ method set_name($name) {
+ $self->{name} = $name;
+ }
+
+ # method with explicit invocant
+ method new($class: %init) {
+ return bless { %init }, $class;
+ }
+
+ # function with default arguments
+ fun search($haystack, $needle = qr/^(?!)/, $offset = 0) {
+ ...
+ }
+
+ # method with default arguments
+ method skip($amount = 1) {
+ $self->{position} += $amount;
+ }
+
+=cut
+
+=pod
+
+ use Function::Parameters qw(:strict);
+
+ fun greet($x) {
+ print "Hello, $x\n";
+ }
+
+ greet "foo", "bar";
+ # Dies at runtime with "Too many arguments for fun greet"
+
+ greet;
+ # Dies at runtime with "Not enough arguments for fun greet"
+
+=cut
+
+=pod
+
+ # use different keywords
+ use Function::Parameters {
+ proc => 'function',
+ meth => 'method',
+ };
+
+ my $f = proc ($x) { $x * 2 };
+ meth get_age() {
+ return $self->{age};
+ }
=head1 DESCRIPTION
This module lets you use parameter lists in your subroutines. Thanks to
-L<Devel::Declare> it works without source filters.
-
-WARNING: This is my first attempt at using L<Devel::Declare> and I have
-almost no experience with perl's internals. So while this module might
-appear to work, it could also conceivably make your programs segfault.
-Consider this module alpha quality.
+L<PL_keyword_plugin|perlapi/PL_keyword_plugin> it works without source filters.
=head2 Basic stuff
To use this new functionality, you have to use C<fun> instead of C<sub> -
C<sub> continues to work as before. The syntax is almost the same as for
C<sub>, but after the subroutine name (or directly after C<fun> if you're
-writing an anonymous sub) you can write a parameter list in parens. This
+writing an anonymous sub) you can write a parameter list in parentheses. This
list consists of comma-separated variables.
The effect of C<fun foo($bar, $baz) {> is as if you'd written
C<sub foo { my ($bar, $baz) = @_; >, i.e. the parameter list is simply
-copied into C<my> and initialized from L<@_|perlvar/"@_">.
+copied into L<my|perlfunc/my-EXPR> and initialized from L<@_|perlvar/"@_">.
-=head2 Advanced stuff
+In addition you can use C<method>, which understands the same syntax as C<fun>
+but automatically creates a C<$self> variable for you. So by writing
+C<method foo($bar, $baz) {> you get the same effect as
+C<sub foo { my $self = shift; my ($bar, $baz) = @_; >.
-If you need L<subroutine attributes|perlsub/"Subroutine Attributes">, you can
-put them after the parameter list with their usual syntax. There's one
-exception, though: you can only use one colon (to start the attribute list);
-multiple attributes have to be separated by spaces.
+=head2 Customizing the generated keywords
-Syntactically, these new parameter lists live in the spot normally occupied
-by L<prototypes|perlsub/"Prototypes">. However, you can include a prototype by
-specifying it as the first attribute (this is syntactically unambiguous
-because normal attributes have to start with a letter).
+You can customize the names of the keywords injected into your scope. To do
+that you pass a reference to a hash mapping keywords to types in the import
+list:
+
+ use Function::Parameters {
+ KEYWORD1 => TYPE1,
+ KEYWORD2 => TYPE2,
+ ...
+ };
+
+Or more concretely:
+
+ use Function::Parameters { proc => 'function', meth => 'method' }; # -or-
+ use Function::Parameters { proc => 'function' }; # -or-
+ use Function::Parameters { meth => 'method' }; # etc.
+
+The first line creates two keywords, C<proc> and C<meth> (for defining
+functions and methods, respectively). The last two lines only create one
+keyword. Generally the hash keys (keywords) can be any identifiers you want
+while the values (types) have to be either a hash reference (see below) or
+C<'function'>, C<'method'>, C<'classmethod'>, C<'function_strict'>,
+C<'method_strict'>, or C<'classmethod_strict'>. The main difference between
+C<'function'> and C<'method'> is that C<'method'>s automatically
+L<shift|perlfunc/shift> their first argument into C<$self> (C<'classmethod'>s
+are similar but shift into C<$class>).
+
+The following shortcuts are available:
+
+ use Function::Parameters;
+ # is equivalent to #
+ use Function::Parameters { fun => 'function', method => 'method' };
+
+=cut
+
+=pod
+
+ use Function::Parameters ':strict';
+ # is equivalent to #
+ use Function::Parameters { fun => 'function_strict', method => 'method_strict' };
+
+=pod
+
+The following shortcuts are deprecated and may be removed from a future version
+of this module:
+
+ # DEPRECATED
+ use Function::Parameters 'foo';
+ # is equivalent to #
+ use Function::Parameters { 'foo' => 'function' };
+
+=cut
+
+=pod
+
+ # DEPRECATED
+ use Function::Parameters 'foo', 'bar';
+ # is equivalent to #
+ use Function::Parameters { 'foo' => 'function', 'bar' => 'method' };
+
+That is, if you want to create custom keywords with L<Function::Parameters>,
+use a hashref, not a list of strings.
+
+You can tune the properties of the generated keywords even more by passing
+a hashref instead of a string. This hash can have the following keys:
+
+=over
+
+=item C<name>
+
+Valid values: C<optional> (default), C<required> (all uses of this keyword must
+specify a function name), and C<prohibited> (all uses of this keyword must not
+specify a function name). This means a C<< name => 'prohibited' >> keyword can
+only be used for defining anonymous functions.
+
+=item C<shift>
+
+Valid values: strings that look like a scalar variable. Any function created by
+this keyword will automatically L<shift|perlfunc/shift> its first argument into
+a local variable whose name is specified here.
+
+=item C<invocant>
+
+Valid values: booleans. This lets users of this keyword specify an explicit
+invocant, that is, the first parameter may be followed by a C<:> (colon)
+instead of a comma and will by initialized by shifting the first element off
+C<@_>.
+
+You can combine C<shift> and C<invocant>, in which case the variable named in
+C<shift> serves as a default shift target for functions that don't specify an
+explicit invocant.
+
+=item C<attributes>, C<attrs>
+
+Valid values: strings that are valid source code for attributes. Any value
+specified here will be inserted as a subroutine attribute in the generated
+code. Thus:
+
+ use Function::Parameters { sub_l => { attributes => ':lvalue' } };
+ sub_l foo() {
+ ...
+ }
+
+turns into
+
+ sub foo :lvalue {
+ ...
+ }
+
+It is recommended that you use C<attributes> in new code but C<attrs> is also
+accepted for now.
+
+=item C<default_arguments>
+
+Valid values: booleans. This property is on by default, so you have to pass
+C<< default_arguments => 0 >> to turn it off. If it is disabled, using C<=> in
+a parameter list causes a syntax error. Otherwise it lets you specify
+default arguments directly in the parameter list:
+
+ fun foo($x, $y = 42, $z = []) {
+ ...
+ }
+
+turns into
+
+ sub foo {
+ my ($x, $y, $z) = @_;
+ $y = 42 if @_ < 2;
+ $z = [] if @_ < 3;
+ ...
+ }
+
+You can even refer to previous parameters in the same parameter list:
+
+ print fun ($x, $y = $x + 1) { "$x and $y" }->(9); # "9 and 10"
+
+This also works with the implicit first parameter of methods:
+
+ method scale($factor = $self->default_factor) {
+ $self->{amount} *= $factor;
+ }
+
+=item C<check_argument_count>
+
+Valid values: booleans. This property is off by default. If it is enabled, the
+generated code will include checks to make sure the number of passed arguments
+is correct (and otherwise throw an exception via L<Carp::croak|Carp>):
+
+ fun foo($x, $y = 42, $z = []) {
+ ...
+ }
+
+turns into
+
+ sub foo {
+ Carp::croak "Not enough arguments for fun foo" if @_ < 1;
+ Carp::croak "Too many arguments for fun foo" if @_ > 3;
+ my ($x, $y, $z) = @_;
+ $y = 42 if @_ < 2;
+ $z = [] if @_ < 3;
+ ...
+ }
+
+=back
+
+Plain C<'function'> is equivalent to:
+
+ {
+ name => 'optional',
+ default_arguments => 1,
+ check_argument_count => 0,
+ }
+
+(These are all default values so C<'function'> is also equivalent to C<{}>.)
+
+C<'function_strict'> is like C<'function'> but with
+C<< check_argument_count => 1 >>.
+
+C<'method'> is equivalent to:
+
+ {
+ name => 'optional',
+ default_arguments => 1,
+ check_argument_count => 0,
+ attributes => ':method',
+ shift => '$self',
+ invocant => 1,
+ }
+
+C<'method_strict'> is like C<'method'> but with
+C<< check_argument_count => 1 >>.
+
+C<'classmethod'> is equivalent to:
+
+ {
+ name => 'optional',
+ default_arguments => 1,
+ check_argument_count => 0,
+ attributes => ':method',
+ shift => '$class',
+ invocant => 1,
+ }
+
+C<'classmethod_strict'> is like C<'classmethod'> but with
+C<< check_argument_count => 1 >>.
+
+=head2 Syntax and generated code
Normally, Perl subroutines are not in scope in their own body, meaning the
-parser doesn't know the name C<foo> or its prototype when processing
-C<sub foo ($) { foo $bar[1], $bar[0]; }>, parsing it as
+parser doesn't know the name C<foo> or its prototype while processing the body
+of C<sub foo ($) { foo $bar[1], $bar[0]; }>, parsing it as
C<$bar-E<gt>foo([1], $bar[0])>. Yes. You can add parens to change the
interpretation of this code, but C<foo($bar[1], $bar[0])> will only trigger
a I<foo() called too early to check prototype> warning. This module attempts
-to fix all of this by adding a subroutine declaration before the definition,
+to fix all of this by adding a subroutine declaration before the function body,
so the parser knows the name (and possibly prototype) while it processes the
body. Thus C<fun foo($x) :($) { $x }> really turns into
-C<sub foo ($); sub foo ($) { my ($x) = @_; $x }>.
+C<sub foo ($) { sub foo ($); my ($x) = @_; $x }>.
+
+If you need L<subroutine attributes|perlsub/Subroutine-Attributes>, you can
+put them after the parameter list with their usual syntax.
+
+Syntactically, these new parameter lists live in the spot normally occupied
+by L<prototypes|perlsub/"Prototypes">. However, you can include a prototype by
+specifying it as the first attribute (this is syntactically unambiguous
+because normal attributes have to start with a letter while a prototype starts
+with C<(>).
+
+As an example, the following declaration uses every available feature
+(subroutine name, parameter list, default arguments, prototype, default
+attributes, attributes, argument count checks, and implicit C<$self> overriden
+by an explicit invocant declaration):
+
+ method foo($this: $x, $y, $z = sqrt 5)
+ :($$$;$)
+ :lvalue
+ :Banana(2 + 2)
+ {
+ ...
+ }
+
+And here's what it turns into:
+
+ sub foo ($$$;$) :method :lvalue :Banana(2 + 2) {
+ sub foo ($$$;$);
+ Carp::croak "Not enough arguments for method foo" if @_ < 3;
+ Carp::croak "Too many arguments for method foo" if @_ > 4;
+ my $this = shift;
+ my ($x, $y, $z) = @_;
+ $z = sqrt 5 if @_ < 3;
+ ...
+ }
+
+Another example:
+
+ my $coderef = fun ($p, $q)
+ :(;$$)
+ :lvalue
+ :Gazebo((>:O)) {
+ ...
+ };
+
+And the generated code:
+
+ my $coderef = sub (;$$) :lvalue :Gazebo((>:O)) {
+ # vvv only if check_argument_count is enabled vvv
+ Carp::croak "Not enough arguments for fun (anon)" if @_ < 2;
+ Carp::croak "Too many arguments for fun (anon)" if @_ > 2;
+ # ^^^ ^^^
+ my ($p, $q) = @_;
+ ...
+ };
+
+=head2 Wrapping Function::Parameters
+
+If you want to wrap L<Function::Parameters>, you just have to call its
+C<import> method. It always applies to the file that is currently being parsed
+and its effects are L<lexical|perlpragma> (i.e. it works like L<warnings> or
+L<strict>).
+
+ package Some::Wrapper;
+ use Function::Parameters ();
+ sub import {
+ Function::Parameters->import;
+ # or Function::Parameters->import(@custom_import_args);
+ }
=head1 AUTHOR
=head1 COPYRIGHT & LICENSE
-Copyright 2009 Lukas Mai.
+Copyright 2010, 2011, 2012 Lukas Mai.
This program is free software; you can redistribute it and/or modify it
under the terms of either: the GNU General Public License as published
projects / p5sagit/Function-Parameters.git / blobdiff