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- .. Copyright (C) 2001-2019 NLTK Project
- .. For license information, see LICENSE.TXT
- ==============================================================================
- Glue Semantics
- ==============================================================================
- .. include:: ../../../nltk_book/definitions.rst
- ======================
- Linear logic
- ======================
- >>> from nltk.sem import logic
- >>> from nltk.sem.glue import *
- >>> from nltk.sem.linearlogic import *
- >>> from nltk.sem.linearlogic import Expression
- >>> read_expr = Expression.fromstring
- Parser
- >>> print(read_expr(r'f'))
- f
- >>> print(read_expr(r'(g -o f)'))
- (g -o f)
- >>> print(read_expr(r'(g -o (h -o f))'))
- (g -o (h -o f))
- >>> print(read_expr(r'((g -o G) -o G)'))
- ((g -o G) -o G)
- >>> print(read_expr(r'(g -o f)(g)'))
- (g -o f)(g)
- >>> print(read_expr(r'((g -o G) -o G)((g -o f))'))
- ((g -o G) -o G)((g -o f))
- Simplify
- >>> print(read_expr(r'f').simplify())
- f
- >>> print(read_expr(r'(g -o f)').simplify())
- (g -o f)
- >>> print(read_expr(r'((g -o G) -o G)').simplify())
- ((g -o G) -o G)
- >>> print(read_expr(r'(g -o f)(g)').simplify())
- f
- >>> try: read_expr(r'(g -o f)(f)').simplify()
- ... except LinearLogicApplicationException as e: print(e)
- ...
- Cannot apply (g -o f) to f. Cannot unify g with f given {}
- >>> print(read_expr(r'(G -o f)(g)').simplify())
- f
- >>> print(read_expr(r'((g -o G) -o G)((g -o f))').simplify())
- f
- Test BindingDict
- >>> h = ConstantExpression('h')
- >>> g = ConstantExpression('g')
- >>> f = ConstantExpression('f')
- >>> H = VariableExpression('H')
- >>> G = VariableExpression('G')
- >>> F = VariableExpression('F')
- >>> d1 = BindingDict({H: h})
- >>> d2 = BindingDict({F: f, G: F})
- >>> d12 = d1 + d2
- >>> all12 = ['%s: %s' % (v, d12[v]) for v in d12.d]
- >>> all12.sort()
- >>> print(all12)
- ['F: f', 'G: f', 'H: h']
- >>> BindingDict([(F,f),(G,g),(H,h)]) == BindingDict({F:f, G:g, H:h})
- True
- >>> d4 = BindingDict({F: f})
- >>> try: d4[F] = g
- ... except VariableBindingException as e: print(e)
- Variable F already bound to another value
- Test Unify
- >>> try: f.unify(g, BindingDict())
- ... except UnificationException as e: print(e)
- ...
- Cannot unify f with g given {}
- >>> f.unify(G, BindingDict()) == BindingDict({G: f})
- True
- >>> try: f.unify(G, BindingDict({G: h}))
- ... except UnificationException as e: print(e)
- ...
- Cannot unify f with G given {G: h}
- >>> f.unify(G, BindingDict({G: f})) == BindingDict({G: f})
- True
- >>> f.unify(G, BindingDict({H: f})) == BindingDict({G: f, H: f})
- True
- >>> G.unify(f, BindingDict()) == BindingDict({G: f})
- True
- >>> try: G.unify(f, BindingDict({G: h}))
- ... except UnificationException as e: print(e)
- ...
- Cannot unify G with f given {G: h}
- >>> G.unify(f, BindingDict({G: f})) == BindingDict({G: f})
- True
- >>> G.unify(f, BindingDict({H: f})) == BindingDict({G: f, H: f})
- True
- >>> G.unify(F, BindingDict()) == BindingDict({G: F})
- True
- >>> try: G.unify(F, BindingDict({G: H}))
- ... except UnificationException as e: print(e)
- ...
- Cannot unify G with F given {G: H}
- >>> G.unify(F, BindingDict({G: F})) == BindingDict({G: F})
- True
- >>> G.unify(F, BindingDict({H: F})) == BindingDict({G: F, H: F})
- True
- Test Compile
- >>> print(read_expr('g').compile_pos(Counter(), GlueFormula))
- (<ConstantExpression g>, [])
- >>> print(read_expr('(g -o f)').compile_pos(Counter(), GlueFormula))
- (<ImpExpression (g -o f)>, [])
- >>> print(read_expr('(g -o (h -o f))').compile_pos(Counter(), GlueFormula))
- (<ImpExpression (g -o (h -o f))>, [])
- ======================
- Glue
- ======================
- Demo of "John walks"
- --------------------
- >>> john = GlueFormula("John", "g")
- >>> print(john)
- John : g
- >>> walks = GlueFormula(r"\x.walks(x)", "(g -o f)")
- >>> print(walks)
- \x.walks(x) : (g -o f)
- >>> print(walks.applyto(john))
- \x.walks(x)(John) : (g -o f)(g)
- >>> print(walks.applyto(john).simplify())
- walks(John) : f
- Demo of "A dog walks"
- ---------------------
- >>> a = GlueFormula("\P Q.some x.(P(x) and Q(x))", "((gv -o gr) -o ((g -o G) -o G))")
- >>> print(a)
- \P Q.exists x.(P(x) & Q(x)) : ((gv -o gr) -o ((g -o G) -o G))
- >>> man = GlueFormula(r"\x.man(x)", "(gv -o gr)")
- >>> print(man)
- \x.man(x) : (gv -o gr)
- >>> walks = GlueFormula(r"\x.walks(x)", "(g -o f)")
- >>> print(walks)
- \x.walks(x) : (g -o f)
- >>> a_man = a.applyto(man)
- >>> print(a_man.simplify())
- \Q.exists x.(man(x) & Q(x)) : ((g -o G) -o G)
- >>> a_man_walks = a_man.applyto(walks)
- >>> print(a_man_walks.simplify())
- exists x.(man(x) & walks(x)) : f
- Demo of 'every girl chases a dog'
- ---------------------------------
- Individual words:
- >>> every = GlueFormula("\P Q.all x.(P(x) -> Q(x))", "((gv -o gr) -o ((g -o G) -o G))")
- >>> print(every)
- \P Q.all x.(P(x) -> Q(x)) : ((gv -o gr) -o ((g -o G) -o G))
- >>> girl = GlueFormula(r"\x.girl(x)", "(gv -o gr)")
- >>> print(girl)
- \x.girl(x) : (gv -o gr)
- >>> chases = GlueFormula(r"\x y.chases(x,y)", "(g -o (h -o f))")
- >>> print(chases)
- \x y.chases(x,y) : (g -o (h -o f))
- >>> a = GlueFormula("\P Q.some x.(P(x) and Q(x))", "((hv -o hr) -o ((h -o H) -o H))")
- >>> print(a)
- \P Q.exists x.(P(x) & Q(x)) : ((hv -o hr) -o ((h -o H) -o H))
- >>> dog = GlueFormula(r"\x.dog(x)", "(hv -o hr)")
- >>> print(dog)
- \x.dog(x) : (hv -o hr)
- Noun Quantification can only be done one way:
- >>> every_girl = every.applyto(girl)
- >>> print(every_girl.simplify())
- \Q.all x.(girl(x) -> Q(x)) : ((g -o G) -o G)
- >>> a_dog = a.applyto(dog)
- >>> print(a_dog.simplify())
- \Q.exists x.(dog(x) & Q(x)) : ((h -o H) -o H)
- The first reading is achieved by combining 'chases' with 'a dog' first.
- Since 'a girl' requires something of the form '(h -o H)' we must
- get rid of the 'g' in the glue of 'see'. We will do this with
- the '-o elimination' rule. So, x1 will be our subject placeholder.
- >>> xPrime = GlueFormula("x1", "g")
- >>> print(xPrime)
- x1 : g
- >>> xPrime_chases = chases.applyto(xPrime)
- >>> print(xPrime_chases.simplify())
- \y.chases(x1,y) : (h -o f)
- >>> xPrime_chases_a_dog = a_dog.applyto(xPrime_chases)
- >>> print(xPrime_chases_a_dog.simplify())
- exists x.(dog(x) & chases(x1,x)) : f
- Now we can retract our subject placeholder using lambda-abstraction and
- combine with the true subject.
- >>> chases_a_dog = xPrime_chases_a_dog.lambda_abstract(xPrime)
- >>> print(chases_a_dog.simplify())
- \x1.exists x.(dog(x) & chases(x1,x)) : (g -o f)
- >>> every_girl_chases_a_dog = every_girl.applyto(chases_a_dog)
- >>> r1 = every_girl_chases_a_dog.simplify()
- >>> r2 = GlueFormula(r'all x.(girl(x) -> exists z1.(dog(z1) & chases(x,z1)))', 'f')
- >>> r1 == r2
- True
- The second reading is achieved by combining 'every girl' with 'chases' first.
- >>> xPrime = GlueFormula("x1", "g")
- >>> print(xPrime)
- x1 : g
- >>> xPrime_chases = chases.applyto(xPrime)
- >>> print(xPrime_chases.simplify())
- \y.chases(x1,y) : (h -o f)
- >>> yPrime = GlueFormula("x2", "h")
- >>> print(yPrime)
- x2 : h
- >>> xPrime_chases_yPrime = xPrime_chases.applyto(yPrime)
- >>> print(xPrime_chases_yPrime.simplify())
- chases(x1,x2) : f
- >>> chases_yPrime = xPrime_chases_yPrime.lambda_abstract(xPrime)
- >>> print(chases_yPrime.simplify())
- \x1.chases(x1,x2) : (g -o f)
- >>> every_girl_chases_yPrime = every_girl.applyto(chases_yPrime)
- >>> print(every_girl_chases_yPrime.simplify())
- all x.(girl(x) -> chases(x,x2)) : f
- >>> every_girl_chases = every_girl_chases_yPrime.lambda_abstract(yPrime)
- >>> print(every_girl_chases.simplify())
- \x2.all x.(girl(x) -> chases(x,x2)) : (h -o f)
- >>> every_girl_chases_a_dog = a_dog.applyto(every_girl_chases)
- >>> r1 = every_girl_chases_a_dog.simplify()
- >>> r2 = GlueFormula(r'exists x.(dog(x) & all z2.(girl(z2) -> chases(z2,x)))', 'f')
- >>> r1 == r2
- True
- Compilation
- -----------
- >>> for cp in GlueFormula('m', '(b -o a)').compile(Counter()): print(cp)
- m : (b -o a) : {1}
- >>> for cp in GlueFormula('m', '((c -o b) -o a)').compile(Counter()): print(cp)
- v1 : c : {1}
- m : (b[1] -o a) : {2}
- >>> for cp in GlueFormula('m', '((d -o (c -o b)) -o a)').compile(Counter()): print(cp)
- v1 : c : {1}
- v2 : d : {2}
- m : (b[1, 2] -o a) : {3}
- >>> for cp in GlueFormula('m', '((d -o e) -o ((c -o b) -o a))').compile(Counter()): print(cp)
- v1 : d : {1}
- v2 : c : {2}
- m : (e[1] -o (b[2] -o a)) : {3}
- >>> for cp in GlueFormula('m', '(((d -o c) -o b) -o a)').compile(Counter()): print(cp)
- v1 : (d -o c) : {1}
- m : (b[1] -o a) : {2}
- >>> for cp in GlueFormula('m', '((((e -o d) -o c) -o b) -o a)').compile(Counter()): print(cp)
- v1 : e : {1}
- v2 : (d[1] -o c) : {2}
- m : (b[2] -o a) : {3}
- Demo of 'a man walks' using Compilation
- ---------------------------------------
- Premises
- >>> a = GlueFormula('\\P Q.some x.(P(x) and Q(x))', '((gv -o gr) -o ((g -o G) -o G))')
- >>> print(a)
- \P Q.exists x.(P(x) & Q(x)) : ((gv -o gr) -o ((g -o G) -o G))
- >>> man = GlueFormula('\\x.man(x)', '(gv -o gr)')
- >>> print(man)
- \x.man(x) : (gv -o gr)
- >>> walks = GlueFormula('\\x.walks(x)', '(g -o f)')
- >>> print(walks)
- \x.walks(x) : (g -o f)
- Compiled Premises:
- >>> counter = Counter()
- >>> ahc = a.compile(counter)
- >>> g1 = ahc[0]
- >>> print(g1)
- v1 : gv : {1}
- >>> g2 = ahc[1]
- >>> print(g2)
- v2 : g : {2}
- >>> g3 = ahc[2]
- >>> print(g3)
- \P Q.exists x.(P(x) & Q(x)) : (gr[1] -o (G[2] -o G)) : {3}
- >>> g4 = man.compile(counter)[0]
- >>> print(g4)
- \x.man(x) : (gv -o gr) : {4}
- >>> g5 = walks.compile(counter)[0]
- >>> print(g5)
- \x.walks(x) : (g -o f) : {5}
- Derivation:
- >>> g14 = g4.applyto(g1)
- >>> print(g14.simplify())
- man(v1) : gr : {1, 4}
- >>> g134 = g3.applyto(g14)
- >>> print(g134.simplify())
- \Q.exists x.(man(x) & Q(x)) : (G[2] -o G) : {1, 3, 4}
- >>> g25 = g5.applyto(g2)
- >>> print(g25.simplify())
- walks(v2) : f : {2, 5}
- >>> g12345 = g134.applyto(g25)
- >>> print(g12345.simplify())
- exists x.(man(x) & walks(x)) : f : {1, 2, 3, 4, 5}
- ---------------------------------
- Dependency Graph to Glue Formulas
- ---------------------------------
- >>> from nltk.corpus.reader.dependency import DependencyGraph
- >>> depgraph = DependencyGraph("""1 John _ NNP NNP _ 2 SUBJ _ _
- ... 2 sees _ VB VB _ 0 ROOT _ _
- ... 3 a _ ex_quant ex_quant _ 4 SPEC _ _
- ... 4 dog _ NN NN _ 2 OBJ _ _
- ... """)
- >>> gfl = GlueDict('nltk:grammars/sample_grammars/glue.semtype').to_glueformula_list(depgraph)
- >>> print(gfl) # doctest: +SKIP
- [\x y.sees(x,y) : (f -o (i -o g)),
- \x.dog(x) : (iv -o ir),
- \P Q.exists x.(P(x) & Q(x)) : ((iv -o ir) -o ((i -o I3) -o I3)),
- \P Q.exists x.(P(x) & Q(x)) : ((fv -o fr) -o ((f -o F4) -o F4)),
- \x.John(x) : (fv -o fr)]
- >>> glue = Glue()
- >>> for r in sorted([r.simplify().normalize() for r in glue.get_readings(glue.gfl_to_compiled(gfl))], key=str):
- ... print(r)
- exists z1.(John(z1) & exists z2.(dog(z2) & sees(z1,z2)))
- exists z1.(dog(z1) & exists z2.(John(z2) & sees(z2,z1)))
- -----------------------------------
- Dependency Graph to LFG f-structure
- -----------------------------------
- >>> from nltk.sem.lfg import FStructure
- >>> fstruct = FStructure.read_depgraph(depgraph)
- >>> print(fstruct) # doctest: +SKIP
- f:[pred 'sees'
- obj h:[pred 'dog'
- spec 'a']
- subj g:[pred 'John']]
- >>> fstruct.to_depgraph().tree().pprint()
- (sees (dog a) John)
- ---------------------------------
- LFG f-structure to Glue
- ---------------------------------
- >>> fstruct.to_glueformula_list(GlueDict('nltk:grammars/sample_grammars/glue.semtype')) # doctest: +SKIP
- [\x y.sees(x,y) : (i -o (g -o f)),
- \x.dog(x) : (gv -o gr),
- \P Q.exists x.(P(x) & Q(x)) : ((gv -o gr) -o ((g -o G3) -o G3)),
- \P Q.exists x.(P(x) & Q(x)) : ((iv -o ir) -o ((i -o I4) -o I4)),
- \x.John(x) : (iv -o ir)]
- .. see gluesemantics_malt.doctest for more
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