(19) Constraint Logic Programming Language: CAL in ESP

	Machine:     PSI
	Environment: SIMPOS
	Language:    ESP
	Source Code: 1.3 MB
	Documents:   Manual (Japanese/English)

Overview

CAL is a sequential constraint logic programming language which can deal with various constraints including non-linear polynomial equations.

Characteristics

Constraint logic programming(CLP) is a scheme of programming language with the following features:

natural, declarative semantics.
clear operational semantics that coincides with the declarative semantics.

This system gives a CLP language CAL and the environment for CAL user.

In CAL system, you can use Context. A context is a constraint set. A new context is created whenever the constraint set is changed. The history of changing contexts is manipulated by the Context Tree, and Current Context is the target of the context manipulation. You can set a context on the context tree arbitrarily as the current context.

Function

A CAL system has any principal functions:

Finding real roots:

The query "find" computes real roots of the univariate equations and returns ont solution. The user can obtain other solutions by backtrack, and branches of the context tree are created.

Context:

CAL system manipulates the history of changing context by the context tree. And you can set a context on the context tree arbitrarily as the current context (the target of the context manipulation).

Various constraint solvers:

CAL system has 4 constraint solvers,

Algebraic constraint solver,
Boolean constraint solver,
Linear constraint solver,
Set constraint solver. The user can specify one of these solvers.

FTP

Constraint Logic Programming Language: CAL in ESP [722K]

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