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=head1 NAME |
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|
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cf::match - object matching language |
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|
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=head1 DESCRIPTION |
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|
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This module implements a simple object matching language. It can be asked |
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to find any (boolean context), or all (list context), matching objects. |
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|
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=head1 MATCH EXAMPLES |
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Match the object if it has a slaying field of C<key1>: |
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slaying = "key1" |
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|
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Match the object if it has an object with name C<force> and |
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slaying C<poison> in it's inventory: |
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|
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has (name = "force" and slaying = "poison") |
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|
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Find all inventory objects with value > 10, which are not invisible: |
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value > 10 and not invisible in inv |
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|
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Find all potions with spell objects inside them in someones inventory: |
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|
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type=SPELL in type=POTION in inv |
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|
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Find all potions inside someones inventory, or inside applied containers: |
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|
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type=POTION also in type=CONTAINER in inv |
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|
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=head1 LANGUAGE |
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|
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# object selection |
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|
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select = set |
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| select also rep 'in' set |
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also = nothing | 'also' |
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rep = nothing | 'rep' | 'repeatedly' |
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|
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set = 'inv' | 'env' | 'map' |
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|
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empty = |
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|
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# object matching |
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|
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match = factor |
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| factor 'and'? match |
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| factor 'or' match |
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|
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factor = 'not' factor |
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| '(' match ')' |
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| expr |
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| expr operator constant |
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|
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operator = '=' | '!=' | '>' | '<' | '<=' | '>=' |
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|
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expr = flag |
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| sattr |
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| aattr '[' <constant> ']' |
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| special |
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| func '(' args ')' |
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| '{' perl code block '}' |
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|
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func = <any function name> |
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sattr = <any scalar object attribute> |
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aattr = <any array object attribute> |
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flag = <any object flag> |
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special = <any ()-less "function"> |
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|
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constant = <number> | '"' <string> '"' | <uppercase cf::XXX name> |
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args = <depends on function> |
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|
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TODO: repeatedly, env |
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|
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=head2 STRUCTURE |
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The two main structures are the C<select>, which selects objects matching |
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various criteria, and the C<match>, which determines if an object matches |
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some desired properties. |
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|
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A C<select> is passed a set of "context objects" that it is applied |
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to. This is initially just one object - for altars, it is the object |
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dropped on it, for pedestals, the object on top of it and so on. |
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|
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This set of context objects can be modified in various ways, for example |
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by replacing it with the inventories of all objects, or all objects on the |
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same mapspace, and so on, by using the C<in> operator. |
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|
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Once the set of context objects has been established, each objetc is |
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matched against the C<match> expression. Sometimes the server is only |
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interested in knowing whether I<anything> matches, and sometimes the |
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server is interested in I<all> objects that match. |
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|
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=head2 OPERATORS |
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|
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=over 4 |
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|
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=item and, or, not, () |
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Match expressions can be combined with C<and> or C<or> to build larger |
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expressions. C<not> negates the expression, and parentheses can be used to |
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group match expressions. |
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|
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Example: match applied weapons. |
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type=WEAPON and applied |
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Example: match horns or rods. |
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type=HORN or type=ROD |
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|
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=item in ... |
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The in operator takes the context set and modifies it in various ways. |
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|
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=over 4 |
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=item in inv |
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Replaces all objects by their inventory. |
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Example: find all spell objects inside the object to be matched. |
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type=SPELL in inv |
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=item in env |
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Replaces all objects by their containing object, if they have one. |
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=item in map |
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Replaces all objects by the objects that are on the same mapspace as them. |
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=item in <match> |
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Finds all context objects matching the match expression, and then puts |
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their inventories into the context set. |
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Note that C<in inv> is simply a special case of an C<< in <match> >> that |
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matches any object. |
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Example: find all spells inside potions inside the inventory of the context |
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object(s). |
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type=SPELL in type=POTION in inv |
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=item also in ... |
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Instead of replacing the context set with something new, the new objects |
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are added to the existing set. |
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Example: check if the context object I<is> a spell, or I<contains> a spell. |
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type=SPELL also in inv |
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=item repeatedly in ... |
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Repeats the operation as many times as possible. This can be used to |
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recursively look into objects. |
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=item also repeatedly in ... |
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C<also> and C<repeatedly> can be combined. |
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Example: check if there are any unpaid items in an inventory, |
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or in the inventories of the inventory objects, and so on. |
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unpaid also repeatedly in inv |
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|
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Example: check if a object is inside a player. |
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type=PLAYER also repeatedly in env |
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=back |
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=back |
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=head2 EXPRESSIONS |
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Match expressions usually consist of simple boolean checks (flag XYZ is |
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set) or simple comparisons. |
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|
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=over 4 |
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=back |
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=head2 FUNCTIONS |
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=over 4 |
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=item has(match) |
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True iff the object has a matching inventory object. |
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=item count(select) |
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Number of matching inventory objects. |
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=back |
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=cut |
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|
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package cf::match; |
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use common::sense; |
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use List::Util (); |
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# parser state |
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# $_ # string to be parsed |
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our $all; # find all, or just the first matching object |
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{ |
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package cf::match::exec; |
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our @ctx; # root object(s) |
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use List::Util qw(first); |
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sub env_chain { |
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my @res; |
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push @res, $_ |
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while $_ = $_->env; |
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@res |
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} |
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package cf::match::parser; |
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use common::sense; |
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sub ws { |
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/\G\s+/gc; |
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} |
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our %func = ( |
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has => sub { |
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'first { ' . &match . ' } $_->inv' |
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}, |
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count => sub { |
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local $all = 1; |
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'(scalar ' . &select . ')' |
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}, |
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); |
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|
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our %special = ( |
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any => sub { |
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1 |
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}, |
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); |
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sub constant { |
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ws; |
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return $1 if /\G([\-\+0-9\.]+)/gc; |
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return "cf::$1" if /\G([A-Z0-9_]+)/gc; |
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#TODO better string parsing, also include '' |
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return $1 if /\G("[^"]+")/gc; |
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die "number, string or uppercase constant name expected\n"; |
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} |
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our $flag = $cf::REFLECT{object}{flags}; |
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our $sattr = $cf::REFLECT{object}{scalars}; |
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our $aattr = $cf::REFLECT{object}{arrays}; |
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|
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sub expr { |
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# ws done by factor |
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my $res; |
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|
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if (/\G ( \{ (?: (?> [^{}]+ ) | (?-1) )* \} ) /gcx) { |
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# perl |
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my $expr = $1; |
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$res .= $expr =~ /\{([^;]+)\}/ ? $1 : "do $expr"; |
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} elsif (/\G([A-Za-z0-9_]+)/gc) { |
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if (my $func = $func{$1}) { |
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/\G\s*\(/gc |
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or die "'(' expected after function name\n"; |
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$res .= $func->(); |
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/\G\s*\)/gc |
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or die "')' expected after function arguments\n"; |
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} elsif (my $func = $special{$1}) { |
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$res .= $func->(); |
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|
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} elsif (exists $flag->{lc $1}) { |
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$res .= "\$_->flag (cf::FLAG_\U$1)"; |
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} elsif (exists $sattr->{$1}) { |
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$res .= "\$_->$1"; |
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} elsif (exists $aattr->{$1}) { |
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$res .= "\$_->$1"; |
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/\G\s*\[/gc |
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or die "'[' expected after array name\n"; |
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$res .= "(" . constant . ")"; |
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/\G\s*\]/gc |
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or die "']' expected after array index\n"; |
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|
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} else { |
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$res .= constant; |
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} |
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|
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} else { |
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die "expr expected\n"; |
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} |
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$res |
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} |
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|
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our %stringop = ( |
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"==" => "eq", |
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"!=" => "ne", |
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"<=" => "le", |
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">=" => "ge", |
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"<" => "lt", |
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">" => "gt", |
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); |
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|
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sub factor { |
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ws; |
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|
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my $res; |
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|
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if (/\Gnot\b\s*/gc) { |
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$res .= "!"; |
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} |
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|
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if (/\G\(/gc) { |
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# () |
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$res .= &match; |
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ws; |
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/\G\)/gc or die "')' expected\n"; |
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|
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} else { |
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my $expr = expr; |
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|
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$res .= $expr; |
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if (/\G\s*([=!<>]=?)/gc) { |
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my $op = $1; |
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$op = "==" if $op eq "="; |
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my $const = constant; |
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$op = $stringop{$op} if $const =~ /^"/; |
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|
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$res .= " $op $const"; |
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} |
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} |
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|
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"($res)" |
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} |
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|
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sub match { |
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my $res = factor; |
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|
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while () { |
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ws; |
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if (/\G(?=also\b|in\b|\)|$)/gc) { |
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# early stop => faster and requires no backtracking |
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last; |
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} elsif (/\Gor\b/gc) { |
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$res .= " || "; |
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} else { |
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/\Gand\b/gc; |
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$res .= " && "; |
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} |
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$res .= factor; |
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} |
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|
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$res |
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} |
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|
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sub select { |
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my $res; |
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|
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my $also; # undef means first iteration |
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while () { |
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if (/\G\s*(inv|env|map)\b/gc) { |
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if ($1 eq "inv") { |
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$res .= " map+(${also}\$_->inv),"; |
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} elsif ($1 eq "env") { |
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$res .= " map+(${also}env_chain), "; |
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} elsif ($1 eq "map") { |
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$res .= " map+(${also}\$_->map->at (\$_->x, \$_->y)),"; |
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} |
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last unless /\G\s*in\b/gc; |
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} else { |
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$res .= " map+($also\$_->inv)," if defined $also; |
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$res .= $all ? " grep { " : " first {"; |
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$res .= match; |
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$res .= "}"; |
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|
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$also = /\G\s*also\b/gc ? '$_, ' : ''; |
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last unless /\G\s*in\b/gc; |
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} |
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} |
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|
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"$res \@ctx" |
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} |
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|
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} |
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|
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sub parse($;$) { |
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local $_ = shift; |
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local $all = shift; |
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|
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my $res = "package cf::match::exec;\n" |
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. eval { cf::match::parser::select }; |
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|
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if ($@) { |
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my $ctx = 20; |
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my $str = substr $_, (List::Util::max 0, (pos) - $ctx), $ctx * 2; |
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substr $str, (List::Util::min $ctx, pos), 0, "<-- HERE -->"; |
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|
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chomp $@; |
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die "$@ ($str)\n"; |
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} |
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|
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$res |
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} |
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|
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my $perl = parse 'flag(SEE_IN_DARK) in inv', 0; |
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|
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warn $perl, "\n";#d# |
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$perl = eval "no warnings; no feature; sub { $perl }"; die if $@; |
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use B::Deparse; |
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warn B::Deparse->new->coderef2text ($perl); |
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|
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exit 0; |
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|
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1; |
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