nltk.sem.linearlogic module

class nltk.sem.linearlogic.ApplicationExpression

Bases: Expression

__init__(function, argument, argument_indices=None)

Parameters

• function – Expression for the function

• argument – Expression for the argument

• argument_indices – set for the indices of the glue formula from which the argument came

Raises

LinearLogicApplicationException – If ‘function’ cannot be applied to ‘argument’ given ‘argument_indices’.

simplify(bindings=None)

Since function is an implication, return its consequent. There should be no need to check that the application is valid since the checking is done by the constructor.

Parameters

bindings – BindingDict A dictionary of bindings used to simplify

Returns

Expression

class nltk.sem.linearlogic.AtomicExpression

Bases: Expression

__init__(name, dependencies=None)

Parameters

• name – str for the constant name

• dependencies – list of int for the indices on which this atom is dependent

compile_neg(index_counter, glueFormulaFactory)

From Iddo Lev’s PhD Dissertation p108-109

Parameters

• index_counter – Counter for unique indices

• glueFormulaFactory – GlueFormula for creating new glue formulas

Returns

(Expression,set) for the compiled linear logic and any newly created glue formulas

compile_pos(index_counter, glueFormulaFactory)

From Iddo Lev’s PhD Dissertation p108-109

Parameters

• index_counter – Counter for unique indices

• glueFormulaFactory – GlueFormula for creating new glue formulas

Returns

(Expression,set) for the compiled linear logic and any newly created glue formulas

initialize_labels(fstruct)

simplify(bindings=None)

If ‘self’ is bound by ‘bindings’, return the atomic to which it is bound. Otherwise, return self.

Parameters

bindings – BindingDict A dictionary of bindings used to simplify

Returns

AtomicExpression

class nltk.sem.linearlogic.BindingDict

Bases: object

__init__(bindings=None)

Parameters

bindings – list [(VariableExpression, AtomicExpression)] to initialize the dictionary dict {VariableExpression: AtomicExpression} to initialize the dictionary

class nltk.sem.linearlogic.ConstantExpression

Bases: AtomicExpression

unify(other, bindings)

If ‘other’ is a constant, then it must be equal to ‘self’. If ‘other’ is a variable, then it must not be bound to anything other than ‘self’.

Parameters

• other – Expression

• bindings – BindingDict A dictionary of all current bindings

Returns

BindingDict A new combined dictionary of of ‘bindings’ and any new binding

Raises

UnificationException – If ‘self’ and ‘other’ cannot be unified in the context of ‘bindings’

class nltk.sem.linearlogic.Expression

Bases: object

applyto(other, other_indices=None)

classmethod fromstring(s)

class nltk.sem.linearlogic.ImpExpression

Bases: Expression

__init__(antecedent, consequent)

Parameters

• antecedent – Expression for the antecedent

• consequent – Expression for the consequent

compile_neg(index_counter, glueFormulaFactory)

From Iddo Lev’s PhD Dissertation p108-109

Parameters

• index_counter – Counter for unique indices

• glueFormulaFactory – GlueFormula for creating new glue formulas

Returns

(Expression,list of GlueFormula) for the compiled linear logic and any newly created glue formulas

compile_pos(index_counter, glueFormulaFactory)

From Iddo Lev’s PhD Dissertation p108-109

Parameters

• index_counter – Counter for unique indices

• glueFormulaFactory – GlueFormula for creating new glue formulas

Returns

(Expression,set) for the compiled linear logic and any newly created glue formulas

initialize_labels(fstruct)

simplify(bindings=None)

unify(other, bindings)

Both the antecedent and consequent of ‘self’ and ‘other’ must unify.

Parameters

• other – ImpExpression

• bindings – BindingDict A dictionary of all current bindings

Returns

BindingDict A new combined dictionary of of ‘bindings’ and any new bindings

Raises

UnificationException – If ‘self’ and ‘other’ cannot be unified in the context of ‘bindings’

exception nltk.sem.linearlogic.LinearLogicApplicationException

Bases: Exception

class nltk.sem.linearlogic.LinearLogicParser

Bases: LogicParser

A linear logic expression parser.

__init__()

Parameters

type_check (bool) – should type checking be performed to their types?

attempt_ApplicationExpression(expression, context)

Attempt to make an application expression. If the next tokens are an argument in parens, then the argument expression is a function being applied to the arguments. Otherwise, return the argument expression.

get_BooleanExpression_factory(tok)

This method serves as a hook for other logic parsers that have different boolean operators

get_all_symbols()

This method exists to be overridden

handle(tok, context)

This method is intended to be overridden for logics that use different operators or expressions

make_BooleanExpression(factory, first, second)

make_VariableExpression(name)

class nltk.sem.linearlogic.Tokens

Bases: object

CLOSE = ')'

IMP = '-o'

OPEN = '('

PUNCT = ['(', ')']

TOKENS = ['(', ')', '-o']

exception nltk.sem.linearlogic.UnificationException

Bases: Exception

__init__(a, b, bindings)

exception nltk.sem.linearlogic.VariableBindingException

Bases: Exception

class nltk.sem.linearlogic.VariableExpression

Bases: AtomicExpression

unify(other, bindings)

‘self’ must not be bound to anything other than ‘other’.

Parameters

• other – Expression

• bindings – BindingDict A dictionary of all current bindings

Returns

BindingDict A new combined dictionary of of ‘bindings’ and the new binding

Raises

UnificationException – If ‘self’ and ‘other’ cannot be unified in the context of ‘bindings’

nltk.sem.linearlogic.demo()