This module provides the basic input/output operations on streams (byte/code input/output and canonical term output). Most predicates are provided in two versions: one that specifies the input or output stream as the first argument and a second which omits this argument and uses the current input or output stream.
From the ISO-Prolog predicates for character input/output, only the _code versions are provided, the _char versions are given by library(iso_char).
Reads from Stream the next character and unifies Code with its character code. At end of stream, unifies Code with the integer -1.
Usage:ISO
Behaves like current_input(S), get_code(S,Code).
Usage:ISO
Reads from Stream the next non-layout character (see code_class/2) and unifies Code with its character code. At end of stream, unifies Code with the integer -1.
Usage:
Behaves like current_input(S), get1_code(S,Code).
Usage:
Unifies Code with the character code of the next character of Stream, leaving the stream position unaltered. At end of stream, unifies Code with the integer -1.
Usage:ISO
Behaves like current_input(S), peek_code(S,Code).
Usage:ISO
Skips just past the next character code Code from Stream.
Usage:
Behaves like current_input(S), skip_code(S,Code).
Usage:
Skips from Stream the remaining input characters on the current line. If the end of the stream is reached, the stream will stay at its end. Portable among different operating systems.
Usage:
Behaves like current_input(S), skip_line(S).
Outputs to Stream the character corresponding to character code Code.
Usage:ISO
Behaves like current_output(S), put_code(S,Code).
Usage:ISO
Outputs a newline character to Stream. Equivalent to put_code(Stream, 0'\n).
Usage:ISO
Behaves like current_output(S), nl(S).
Usage:ISO
Outputs Num spaces to Stream.
Usage:
Behaves like current_output(S), tab(S,Num).
Usage:
Unifies Class with an integer corresponding to the lexical class of the character whose code is Code, with the following correspondence:
0 - layout (includes space, newline, tab) 1 - small letter 2 - capital letter (including '_') 3 - digit 4 - graphic (includes #$&*+-./:<=>?@^\`~ ) 5 - punctuation (includes !;"'%(),[]{|} ) 6 - extended identifier continuation 7 - invalidNote that in ISO-Prolog the back quote ` is a punctuation character, whereas in Ciao it is a graphic character. Thus, if compatibility with ISO-Prolog is desired, the programmer should not use this character in unquoted names.
Usage:
String is the list of the character codes encoded by the list of bytes Bytes (equivalent to String=Bytes if any of the lists is a list of ASCII codes).
Reads from the current input stream the next character, unifying Code with its character code, and Type with its lexical class. At end of stream, unifies both Code and Type with the integer -1. Equivalent to
get(Code), (Code = -1 -> Type = -1 ; code_class(Code,Type))
Usage:
Reads from the current input stream the next non-layout character, unifying Code with its character code, and Type with its lexical class (which will be nonzero). At end of stream, unifies both Code and Type with the integer -1. Equivalent to
get1(Code), (Code = -1 -> Type = -1 ; code_class(Code,Type))
Usage:
Reads from Stream the next byte and unifies it with Byte. At end of stream, unifies Byte with the integer -1.
Usage:ISO
Behaves like current_input(S), get_byte(S,Byte).
Usage:ISO
Unifies Byte with the next byte of Stream, leaving the stream position unaltered. At end of stream, unifies Byte with the integer -1.
Usage:ISO
Behaves like current_input(S), peek_byte(S,Byte).
Usage:ISO
Outputs to Stream the byte Byte.
Usage:ISO
Behaves like current_output(S), put_byte(S,Byte).
Usage:ISO
Stream has a stream position end-of-stream or past-end-of-stream. This predicate is provided for ISO compatibility, but its usage is discouraged, since it cannot reliably detect that no more data is available in the stream (e.g., without blocking). Use peek_byte/2 or peek_code/2 instead.
Usage:ISO
Behaves like current_input(S), at_end_of_stream(S).
Displays Term onto Stream. Lists are output using list notation, the other compound terms are output in functional notation. Similar to write_term(Stream, Term, [ignore_ops(ops)]), except that curly bracketed notation is not used with {}/1, and the write_strings flag is not honored.
Usage:
Behaves like current_output(S), display(S,Term).
Usage:
Similar to display(Stream, Term), but atoms and functors that can't be read back by read_term/3 are quoted. Thus, similar to write_term(Stream, Term, [quoted(true), ignore_ops(ops)]), with the same exceptions as display/2.
Usage:
Behaves like current_output(S), displayq(S,Term).
Usage: