1		:- multifile generate/2.
2		:- multifile shrink/3.
3
4		:- use_module(library(random),[random/3,random_member/2]).
5
6		generate(prob_ast_int_expr,Value) :-
7		generate(prob_ast_int_expr([]),Value).
8
9		% Options:
10		% not-well-defined
11		% id to enable random generation of identifier
12		% all options of any type are accepted and will be applied when valid
13
14		% Expr :: integer
15		generate(prob_ast_int_expr(Options),Value) :-
16		% double the chance of generating recursive expression
17		% (i.e. add,minus,multiplication,div,unary_minus) to increase depth,
18		% because modulo and power_of also just generate ground integer nodes for well-definedness
19		random_member(Expr,[add,minus,multiplication,div,unary_minus,
20		modulo,power_of,max,min,max_int,min_int,
21		add,minus,multiplication,div,unary_minus]) ,
22		generate(prob_ast_int_expr(Expr,Options),Value).
23
24		generate(prob_ast_int_expr(card,Options),b(card(Set),integer,[])) :-
25		random_member(Type,[integer([]),string([]),boolean([])]) ,
26		(member(id,Options)
27		-> generate(id_or_ast(set(Type)),Set)
28		; generate(prob_ast_set(Type,Options),Set)).
29
30		% also generate empty list for no well-definedness
31		generate(prob_ast_int_expr(Expr,Options),b(NewPred,integer,[])) :-
32		memberchk(not-well-defined,Options) ,
33		!,
34		member(Expr,[max,min]) ,
35		random(0,9,R) ,
36		(R > 3
37		-> generate(prob_ast_set(integer([small]),[extension|Options]),Set)
38		; generate(prob_ast_set(empty([]),Options),Set)) ,
39		NewPred =.. [Expr,Set].
40		generate(prob_ast_int_expr(Expr,Options),b(NewPred,integer,[])) :-
41		member(Expr,[max,min]) ,
42		generate(prob_ast_set(integer([small]),[extension|Options]),Set) , % no expression
43		NewPred =.. [Expr,Set].
44
45		generate(prob_ast_int_expr(Expr,_),b(Expr,integer,[])) :-
46		member(Expr,[max_int,min_int]).
47
48		generate(prob_ast_int_expr(Expr,Options),b(NewPred,integer,[])) :-
49		member(Expr,[add,minus,multiplication]) ,
50		Type = integer([small,random|Options]) ,
51		generate_aux(Options,Type,Type,A,B) ,
52		NewPred =.. [Expr,A,B].
53
54		generate(prob_ast_int_expr(Expr,Options),b(NewPred,integer,[])) :-
55		memberchk(not-well-defined,Options) ,
56		!,
57		memberchk(Expr,[modulo,power_of,div]) ,
58		% generate expressions (not well defined for zero, negative values or float)
59		TypeA = integer([small,random,not-well-defined|Options]) ,
60		TypeB = integer([small,not-well-defined|Options]) ,
61		generate_aux(Options,TypeA,TypeB,A,B) ,
62		NewPred =.. [Expr,A,B].
63		% use really small numbers to receive well-definedness for
64		% integer expressions in predicates
65		generate(prob_ast_int_expr(power_of,Options),b(NewPred,integer,[])) :-
66		Type = integer([between(0,7)|Options]) ,
67		% disabled generation of identifier
68		/*(member(id,Options) ->
69		generate(id_or_ast(Type),A) ,
70		generate(id_or_ast(Type),B)
71		;*/ gen_type(Type,ast,NType) ,
72		generate(NType,A) ,
73		generate(NType,B),
74		NewPred =.. [power_of,A,B].
75		generate(prob_ast_int_expr(modulo,Options),b(NewPred,integer,[])) :-
76		TypeA = integer([small,positive|Options]) ,
77		TypeB = integer([small,positive,nozero|Options]) ,
78		generate_aux(Options,TypeA,TypeB,A,B) ,
79		NewPred =.. [modulo,A,B].
80		generate(prob_ast_int_expr(div,Options),b(div(A,B),integer,[])) :-
81		TypeA = integer([small,random|Options]) ,
82		TypeB = integer([small,positive,nozero|Options]) ,
83		generate_aux(Options,TypeA,TypeB,A,B).
84
85		generate(prob_ast_int_expr(unary_minus,Options),b(unary_minus(Expr),integer,[])) :-
86		Type = integer([small,random|Options]) ,
87		(member(id,Options)
88		-> generate(id_or_ast(Type),Expr)
89		; gen_type(Type,ast,NType) ,
90		generate(NType,Expr)).
91
92		generate(prob_ast_int_expr(size),b(size(Seq),integer,[])) :-
93		generate(ground_type,Type) ,
94		generate(prob_ast_seq(Type),Seq).
95
96		% generate two nodes for given types and options
97		generate_aux(Options,TypeA,TypeB,NodeA,NodeB) :-
98		member(id,Options) , ! ,
99		generate(id_or_ast(TypeA),NodeA) ,
100		generate(id_or_ast(TypeB),NodeB).
101		generate_aux(_,TypeA,TypeB,NodeA,NodeB) :-
102		gen_type(TypeA,ast,NTypeA) , generate(NTypeA,NodeA) ,
103		gen_type(TypeB,ast,NTypeB) , generate(NTypeB,NodeB).
104
105		shrink(Type,Expression,Shrunken) :-
106		Type =.. [prob_ast_int_expr|_] ,
107		minimize_int_expr(Expression,Shrunken).
108		shrink(Type,Expression,Shrunken) :-
109		Type =.. [prob_ast_int_expr|_] ,
110		get_inner_expr(Expression,Shrunken).