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###############################################################################
# Top contributors (to current version):
# Alex Ozdemir
#
# This file is part of the cvc5 project.
#
# Copyright (c) 2009-2025 by the authors listed in the file AUTHORS
# in the top-level source directory and their institutional affiliations.
# All rights reserved. See the file COPYING in the top-level source
# directory for licensing information.
# #############################################################################
#
# An example of using inductive datatypes in cvc5.
##
from cvc5.pythonic import *
if __name__ == '__main__':
# This example builds a simple "cons list" of integers, with
# two constructors, "cons" and "nil."
# Building a datatype consists of two steps.
# First, the datatype is specified.
# Second, it is "resolved" to an actual sort, at which point function
# symbols are assigned to its constructors, selectors, and testers.
decl = Datatype("list")
decl.declare("cons", ("head", IntSort()), ("tail", decl))
decl.declare("nil")
List = decl.create()
# Using constructors and selectors:
t = List.cons(0, List.nil)
print("t is:", t)
print("head of t is:", List.head(t))
print("after simplify:", simplify(List.head(t)))
print()
# You can iterate over constructors and selectors
for i in range(List.num_constructors()):
ctor = List.constructor(i)
print("ctor:", ctor)
for j in range(ctor.arity()):
print(" + arg:", ctor.domain(j))
print(" + selector:", List.accessor(i, j))
print()
# You can use testers
print("t is a 'cons':", simplify(List.is_cons(t)))
print()
# This Python API does not support type parameters or updators for
# datatypes. See the base Python API for those features, or construct them
# using Python functions/classes.
a = Int('a')
solve(List.head(List.cons(a, List.nil)) > 50)
prove(Not(List.is_nil(List.cons(a, List.nil))))
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