portray {rolog}

Translate an R call to a prolog compound and pretty print it

Description

Translate an R call to a prolog compound and pretty print it

Usage

portray(
  query = call("member", expression(X), list(quote(a), "b", 3L, 4, TRUE, expression(Y))),
  options = NULL
)

Arguments

query

an R call. The R call consists of symbols, integers and real numbers, character strings, boolean values, expressions and lists, and other calls. Vectors of booleans, integers, floating point numbers, and strings with length N > 1 are translated to prolog compounds !/N, %/N, #/N and $$/N, respectively. The names can be modified with the options below.

options

This is a list of options controlling translation from and to prolog.

• boolvec (see option rolog.boolvec, default is !) is the name of the prolog compound for vectors of booleans.

• intvec, realvec, charvec define the compound names for vectors of integers, doubles and strings, respectively (defaults are %, # and $$).

• If scalar is TRUE (default), vectors of length 1 are translated to scalar prolog elements. If scalar is FALSE, vectors of length 1 are also translated to compounds.

Details

The R elements are translated to the following prolog citizens:

• numeric -> real (vectors of size N -> #/N)

• integer -> integer (vectors -> %/N)

• character -> string (vectors -> $$/N)

• symbol/name -> atom

• expression -> variable

• call/language -> compound

• boolean -> true, false (atoms)

• list -> list

Value

character string with the prolog syntax of the call

See Also

rolog_options() for fine-grained control over the translation