lambeq.rewrite

class lambeq.rewrite.CoordinationRewriteRule(words: Optional[Container[str]] = None)

Bases: lambeq.rewrite.base.RewriteRule

A rewrite rule for coordination.

This rule matches the word ‘and’ with codomain a.r @ a @ a.l for pregroup type a, and replaces the word, based on [Kar2016], with a layer of interleaving spiders.

__call__(box: discopy.rigid.Box) → Optional[discopy.rigid.Diagram]

Apply the rewrite rule to a box.

Parameters

boxdiscopy.rigid.Box

The candidate box to be tested against this rewrite rule.

Returns

discopy.rigid.Diagram, optional

The rewritten diagram, or None if rule does not apply.

Notes

The default implementation uses the matches() and rewrite() methods, but derived classes may choose to not use them, since the default Rewriter implementation does not call those methods directly, only this one.

__init__(words: Optional[Container[str]] = None) → None

Instantiate a CoordinationRewriteRule.

Parameters

wordscontainer of str, optional

A list of words to be rewritten by this rule. If a box does not have one of these words, it will not be rewritten, even if the codomain matches. If omitted, the rewrite applies only to the word “and”.

matches(box: discopy.rigid.Box) → bool

Check if the given box should be rewritten.

rewrite(box: discopy.rigid.Box) → discopy.rigid.Diagram

Rewrite the given box.

class lambeq.rewrite.CurryRewriteRule

Bases: lambeq.rewrite.base.RewriteRule

A rewrite rule using map-state duality.

__call__(box: discopy.rigid.Box) → Optional[discopy.rigid.Diagram]

Apply the rewrite rule to a box.

Parameters

boxdiscopy.rigid.Box

The candidate box to be tested against this rewrite rule.

Returns

discopy.rigid.Diagram, optional

The rewritten diagram, or None if rule does not apply.

Notes

The default implementation uses the matches() and rewrite() methods, but derived classes may choose to not use them, since the default Rewriter implementation does not call those methods directly, only this one.

__init__() → None

Instantiate a CurryRewriteRule.

This rule uses the map-state duality by iteratively uncurrying on both sides of each box. When used in conjunction with normal_form(), this removes cups from the diagram in exchange for depth. Diagrams with less cups become circuits with less post-selection, which results in faster QML experiments.

matches(box: discopy.rigid.Box) → bool

Check if the given box should be rewritten.

rewrite(box: discopy.rigid.Box) → discopy.rigid.Diagram

Rewrite the given box.

class lambeq.rewrite.RewriteRule

Bases: abc.ABC

Base class for rewrite rules.

__call__(box: discopy.rigid.Box) → Optional[discopy.rigid.Diagram]

Apply the rewrite rule to a box.

Parameters

boxdiscopy.rigid.Box

The candidate box to be tested against this rewrite rule.

Returns

discopy.rigid.Diagram, optional

The rewritten diagram, or None if rule does not apply.

Notes

The default implementation uses the matches() and rewrite() methods, but derived classes may choose to not use them, since the default Rewriter implementation does not call those methods directly, only this one.

abstract matches(box: discopy.rigid.Box) → bool

Check if the given box should be rewritten.

abstract rewrite(box: discopy.rigid.Box) → discopy.rigid.Diagram

Rewrite the given box.

class lambeq.rewrite.Rewriter(rules: Optional[Iterable[Union[str, RewriteRule]]] = None)

Bases: object

Class that rewrites diagrams.

Comes with a set of default rules.

__call__(diagram: discopy.rigid.Diagram) → discopy.rigid.Diagram

Apply the rewrite rules to the given diagram.

__init__(rules: Optional[Iterable[Union[str, RewriteRule]]] = None) → None

Initialise a rewriter.

Parameters

rulesiterable of str or RewriteRule, optional

A list of rewrite rules to use. RewriteRule instances are used directly, str objects are used as names of the default rules. See Rewriter.available_rules() for the list of rule names. If omitted, all the default rules are used.

add_rules(*rules: Union[str, lambeq.rewrite.base.RewriteRule]) → None

Add rules to this rewriter.

classmethod available_rules() → list[str]

The list of default rule names.

class lambeq.rewrite.SimpleRewriteRule(cod: Ty, template: Diagram, words: Optional[Container[str]] = None, case_sensitive: bool = False)

Bases: lambeq.rewrite.base.RewriteRule

A simple rewrite rule.

This rule matches each box against a required codomain and, if provided, a set of words. If they match, the word box is rewritten into a set template.

__call__(box: discopy.rigid.Box) → Optional[discopy.rigid.Diagram]

Apply the rewrite rule to a box.

Parameters

boxdiscopy.rigid.Box

The candidate box to be tested against this rewrite rule.

Returns

discopy.rigid.Diagram, optional

The rewritten diagram, or None if rule does not apply.

Notes

The default implementation uses the matches() and rewrite() methods, but derived classes may choose to not use them, since the default Rewriter implementation does not call those methods directly, only this one.

__init__(cod: Ty, template: Diagram, words: Optional[Container[str]] = None, case_sensitive: bool = False) → None

Instantiate a simple rewrite rule.

Parameters

coddiscopy.rigid.Ty

The type that the codomain of each box is matched against.

templatediscopy.rigid.Diagram

The diagram that a matching box is replaced with. A special placeholder box is replaced by the word in the matched box, and can be created using SimpleRewriteRule.placeholder().

wordscontainer of str, optional

If provided, this is a list of words that are rewritten by this rule. If a box does not have one of these words, it is not rewritten, even if the codomain matches. If omitted, all words are permitted.

case_sensitivebool, default: False

This indicates whether the list of words specified above are compared case-sensitively. The default is False.

matches(box: discopy.rigid.Box) → bool

Check if the given box should be rewritten.

classmethod placeholder(cod: discopy.rigid.Ty) → discopy.grammar.pregroup.Word

Helper function to generate the placeholder for a template.

Parameters

coddiscopy.rigid.Ty

The codomain of the placeholder, and hence the word in the resulting rewritten diagram.

Returns

discopy.rigid.Box

A placeholder box with the given codomain.

rewrite(box: discopy.rigid.Box) → discopy.rigid.Diagram

Rewrite the given box.