This module contains predicates for working with DCGs defined over sequences of character codes. Some of the predicates can only be used to generate sequences, not parse them.

 writedcg(+P:phrase) is nondet

Run the phrase P, which must be a standard list-of-codes DCG, and print the output.

 phrase_string(+P:phrase, -S:string) is nondet

phrase_string(+P:phrase, +S:string) is nondet

Use list-of-codes DCG phrase P to parse or generate a string S.

 phrase_atom(+P:phrase, -A:atom) is nondet

phrase_atom(+P:phrase, +A:atom) is nondet

Use list-of-codes DCG phrase P to parse or generate a atom A.

 ctype(Type)// is nondet

Matches a code C that satisfies code_type(C,Type). See char_type/2 for listing of types.

 null// is det

Empty string.

 cr// is det

Carriage return "\n".

 sp// is det

Space " ".

 fs// is det

Full stop (period) ".".

 fssp// is det

Full stop (period) followed by space.

 tb// is det

Tab "\t".

 comma// is det

Comma ",".

 commasp// is det

Comma and space ", ".

 at(+X:atom)// is det

Generate code list for textual representation of atom X.

 wr(+X:term)// is det

Generate the list of codes for term X, as produced by write/1.

 str(+X:term)// is det

Generate the list of codes for string X, as produced by writeq/1.

 fmt(+F:atom, +Args:list)// is det

Generate list of codes using format/3.

 padint(+N:integer, +Range, +X:integer)// is det

padint(+N:integer, +Range, -X:integer)// is nondet

Write integer X padded with zeros ("0") to width N.

 brace(+P:phrase)// is nondet

Generate "{" before and "}" after the phrase P.

 paren(+P:phrase)// is nondet

Generate "(" before and ")" after the phrase P.

 sqbr(+P:phrase)// is nondet

Generate "[" before and "]" after the phrase P.

 q(+P:phrase)// is nondet

Generate list of codes from phrase P, surrounds it with single quotes, and escapes (by doubling up) any internal quotes so that the generated string is a valid quoted string. Must be list of codes DCG.

 qq(+P:phrase)// is nondet

Generate list of codes from phrase P, surrounds it with double quotes, and escapes (by doubling up) any double quotes so that the generated string is a valid double quoted string.

 escape(+Q:C, +P:phrase)// is nondet

Runs phrase P to generate a list of elements of type C and then escapes any occurrences of Q by doubling them up, e.g., escape(39,"some 'text' here") doubles up the single quotes yielding "some ''text'' here".

 escape_with(+E:C, +Q:C, +P:phrase)// is nondet

Runs phrase P to generate a list of elements of type C and then escapes any occurrences of Q by prefixing them with E, e.g., escape_with(92,39,"some 'text' here") escapes the single quotes with backslashes, yielding "some \'text\' here".

 esc(+Esc:esc, +Codes:list(code))// is det

esc(+Esc:esc, -Codes:list(code))// is nondet

Parser for a sequence of characters involving escape sequences. These are recognised by the predicate Esc, whose type is

esc == pred(list(codes),list(codes))//.

The DCG goal esc(H,T) matches an escaped sequence in the string and unifies H-T with a difference list representing it's internal or semantic form. Esc must not place any constraints on the difference list tail T.

Starts with the longest possible match and retrieves shorter matches on backtracking.