phrase/2 — Logtalk 3.100.1

built-in method

# `phrase/2`

## Description

    phrase(GrammarRuleBody, Input)
    phrase(::GrammarRuleBody, Input)
    phrase(Object::GrammarRuleBody, Input)

True when the `GrammarRuleBody` grammar rule body can be applied to the `Input` list of tokens. In the most common case, `GrammarRuleBody` is a non-terminal defined by a grammar rule. This built-in method is declared private and thus cannot be used as a message to an object. When using a backend Prolog compiler supporting a module system, calls in the format `phrase(Module:GrammarRuleBody, Input)` may also be used.

This method is opaque to cuts in the first argument. When the first argument is sufficiently instantiated at compile-time, the method call is compiled in order to eliminate the implicit overheads of converting the grammar rule body into a goal and meta-calling it. For performance reasons, the second argument is only type-checked at compile-time.

## Meta-predicate template

    phrase(2, *)

## Modes and number of proofs

    phrase(+callable, ?list) - zero_or_more

## Errors

`GrammarRuleBody` is a variable:
`instantiation_error`
`GrammarRuleBody` is neither a variable nor a callable term:
`type_error(callable, GrammarRuleBody)`

## Examples

To parse a list of tokens using a local non-terminal:
`phrase(NonTerminal, Input)`
To parse a list of tokens using a non-terminal within the scope of self:
`phrase(::NonTerminal, Input)`
To parse a list of tokens using a public non-terminal of an explicit object:
`phrase(Object::NonTerminal, Input)`

See also

call//1-N, phrase//1, phrase/3