ISO/IEC 13211-1:1995

INTERNATIONAL
ISO/IEC
STANDARD
13211-1
First edition
1995-06-01
Information technology - Programming
languages - Prolog -
Part 1:
General core
Technologies de I’informa tion
- Langages de programmation -
Prolog -
Partie 1: Noyau g&Gral
ISO/IEC 13211-1 : 1995(E)
Page
Contents
. . .
~111
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ix
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 Scope .
..........................................
1.1 Notes
2 Normative references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.............................. 10
4 Symbols and abbreviations
........................................ 10
4.1 Notation
....................... 10
4.1.1 Basic mathematical types
................... 10
4.1.2 Mathematical and set Operators
.............................. 10
4.1.3 Other functions
............................ 11
Abstract data type: Stack
4.2
.......................... 11
4.3 Abstract data type: mapping
......................................... 11
5 Compliance
.................................. 11
5.1 Prolog processor
...................................... 12
5.2 Prolog text
...................................... 12
Prolog goal
5.3
...................................
5.4 Documentation.
....................................... 12
5.5 Extensions
.................................... 12
5.5.1 Syntax
.......................... 12
5.5.2 Predefined Operators
.................... 12
5.5.3 Character-conversion mapping
.................................... 12
5.5.4 Types.
.................................. 13
5.5.5 Directives
................................ 13
5.5.6 Side effects
............................ 13
5.5.7 Control constructs
..................................... 13
5.5.8 Flags
............................ 13
5.5.9 Built-in predicates
@ ISO/IEC 1995
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Printed in Switzerland
ii
ISO/IEC 132114 : 1995(E)
@ ISO/IEC 1995
5.510 Evaluable functors . 13
55.11 Reserved atoms. . 13
6 Syntax .
........................................ 13
6.1 Notation
........................... 13
6.1.1 Backus Naur Form
.......................... 14
6.1.2 Abstract term Syntax
............................... 15
6.2 Prolog text and data.
................................. 15
6.2.1 Prolog text
................................ 15
6.2.2 Prolog data.
.......................................... 15
6.3 Terms
............................... 16
6.3.1 Atomic terms
..................................
6.3.2 Variables 16
6.3.3 Compound terms - functional notation . 16
6.3.4 Compound terms - Operator notation .
6.3.5 Compound terms - list notation . 19
............ 20
6.3.6 Compound terms - curly bracketed term
............... 20
6.3.7 Terms - double quoted list notation
......................................... 20
6.4 Tokens
................................ 21
6.4.1 Layout text.
.................................... 21
6.4.2 Names
.................................. 23
6.4.3 Variables
............................. 23
6.4.4 Integer numbers
6.4.5 Floating Point numbers . 23
........................... 24
6.4.6 Double quoted lists
........................... 24
6.4.7 Back quoted strings
................................ 24
6.4.8 Other tokens
.............................. 24
6.5 Processor Character set
............................ 25
6.5.1 Graphit characters
6.5.2 Alphanumeric characters . 25
6.5.3 Solo characters . 25
6.5.4 Layout characters . 25
6.5.5 Meta characters . 26
6.6 Collating sequence . 26
......................... 26
7 Language concepts and semantics
.......................................... 27
7.1 Types
................................... 27
7.1.1 Variable
.................................... 27
7.1.2 Integer
............................... 28
7.1.3 Floating Point
7.1.4 Atom . 29
7.1.5 Compound term . 29
7.1.6 Related terms . 29
...................................... 30
7.2 Term Order
7.2.1 Variable . 31
...............................
7.2.2 Floating Point 31
.................................... 31
7.2.3 Integer
..................................... 31
7.2.4 Atom
7.2.5 Compound . 31
......................................
7.3 Unification 31
..................... 31
7.3.1 The mathematical definition
...........................
7.3.2 Herbrand algorithm 31
7.3.3 Subject to occurs-check (STO) and not subject to occurs-
check (NSTO) .
.................... 33
7.3.4 Normal unification in Prolog
...................................... 33
7.4 Prolog text
7.4.1 Undefined features . 34
. . .
@ ISO/IEC 1995
ISO/IEC 13211-1 : 1995(E)
..................................
7.4.2 Directives
................................... 35
7.4.3 Clauses
........................................ 36
7.5 Database
.............. 36
7.5.1 Preparing a Prolog text for execution
...................
7.5.2 Static and dynamic procedures
....................
Private and public procedures
7.5.3
......................
A logical database update
7.5.4
........ 37
7.6 Converting a term to a clause, and a clause to a term
........... 37
7.6.1 Converting a term to the head of a clause
.......... 37
7.6.2 Converting a term to the body of a clause.
........... 37
7.6.3 Converting the head of a clause to a term
.......... 38
7.6.4 Converting the body of a clause to a term.
............................. 38
7.7 Executing a Prolog goal
.................................. 38
7.7.1 Execution
............... 38
7.7.2 Data types for the execution model-
................................ 39
7.7.3 Initialization
............................. 39
7.7.4 A goal succeeds
................................ 39
7.7.5 A goal fails
........................... 39
7.7.6 Re-executing a goal
.................. 40
7.7.7 Selecting a clause for execution
................................ 40
7.7.8 Backtracking
................................ 40
7.7.9 Side effects
................ 40
7.7.10 Executing a user-defined procedure
7.7.11 Executing a user-defined procedure with no more clauses
.................... 42
7.7.12 Executing a built-in predicate
................................. 43
7.8 Control constructs
.................................... 43
7.8.1 truel0.
..................................... 43
7.8.2 fail/O
.....................................
7.8.3 callll
7.8.4 !/O - tut .
..........................
7.8.5 (‘,‘)/2 - conjunction
............................ 47
(;)/2 - disjunction
7.8.6
.............................. 49
(->)/2 - if-then
7.8.7
............................ 50
7.8.8 (;)/2 - if-then-else
.................................... 51
7.8.9 catch/3
................................... 53
7.8.10 throwfl
.............................
7.9 Evaluating an expression
................................. 54
7.9.1 Description
.................................... 54
7.9.2 Errors
...................................... 54
7.10 Input/output
............................ 54
7.10.1 Sources and sinks
................................... 55
7.10.2 Streams
............................. 58
7.10.3 Read-Options list
............................ 58
7.10.4 Write-Options list
.............................. 59
7.10.5 Writing a term
.......................................... 60
7.11 Flags
.................... 60
7.11.1 Flags defining integer type 1
................................. 61
7.11.2 Other flags
.......................................... 61
7.12 Errors
......................... 62
7.12.1 The effect of an error
........................... 62
7.12.2 Error classification
.................................... 63
8 Built-in predicates
................
8.1 The format of built-in predicate definitions
................................. 63
8.1.1 Description
.......................... 64
S.l.2 Template and modes
.................................... 64
8.1.3 Errors
iv
@ ISO/IEC 1995 ISO/IEC 132114 : 1995(E)
.................................. 65
8.1.4 Examples
8.1.5 Bootstrapped built-in predicates . , , , , , . , , , . , , , , , , ,
................................... 65
8.2 Term unification
.......................... 65
8.2.1 (=)/2 - Prolog unify
8.2.2 unify_with_occurs_check/2 - unify . . , , , , , , , , , , , , , . .
8.2.3 (\=)/2 - . 67
not Prolog unifiable
..................................... 67
8.3 Type testing
..................................... 67
8.3.1 var/l
.................................... 68
8.3.2 atom/l
................................... 68
8.3.3 integer/1
.................................... 68
8.3.4 floatll
................................... 68
8.3.5 atomic/l
................................ 69
8.3.6 compound/l
................................... 69
8.3.7 nonvar/l
.................................. 69
8.3.8 number/l
.................................. 70
8.4 Term comparison
8.4.1 (@=<)/2 - term less than or equal, (==)/2 - term identical,
(\==)/2 - term not identical, (@<)/2 - term less than,
(@>)/2 - term greater than, (@>=)/2 - term greater than
or equal . 70
....................... 71
8.5 Term creation and decomposition
.................................. 71
8.5.1 functor/3
8.5.2 arg/3 . 72
8.5.3 (=.)/ 2 - univ . 72
8.5.4 copy-term/2 . 73
............................... 74
8.6 Arithmetic evaluation
8.6.1 (is)/2 - evaluate expression . 74
8.7 Arithmetic comparison . 74
8.7.1 (=:=)/2 - arithmetic equal, (=\=)/2 - arithmetic not equal,
(<)/2 - arithmetic less than, (=<)/2 - arithmetic less
than or equal, (>)/2 - arithmetic greater than, (>=)/2 -
arithmetic greater than or equal . 76
8.8 Clause retrieval and information . 77
................................... 77
8.8.1 clause/2
............................ 78
8.8.2 current-predicate/l
........................ 78
8.9 Clause creation and destruction
................................... 78
8.9.1 asserta/l
................................... 79
8.9.2 assertz/l
................................... 80
8.9.3 retract/l
.................................. 81
8.9.4 abolishll
..................................... 82
8.10 All solutions
................................... 82
8.10.1 findall/
................................... 83
8.10.2 bagof/3
.................................... 84
8.10.3 setof/3
.......................... 86
8.11 Stream selection and control
8.11.1 currenL.input/l . 86
8.11.2 current-output/1 . 86
................................. 87
8.11.3 set-input/l
................................ 87
8.11.4 set-output/1
8.11.5 open/4, open/3 . 87
8.11.6 close/2, close/l . 88
.................... 89
8.11.7 flush-output/l, flush-output/0
8.11.8 stream_property/2, at-end-ofstream/O, at-end-of-strearn/l . 89
.......................... 90
8.11.9 set_stream_position/2
.............................. 9 1
8.12 Character input/output
8.12.1 get_char/2, getcharll , get-Code/1 , get-Code/2 . 9 1
8.12.2 peek_char/2, peek-charll , peek-codell , peekcodel2 . 92
V
@ ISO/IEC 1995
ISO/IEC 13211-1 : 1995(E)
8.12.3 put-charl2, put-charll, put-codell, putcodel2, nl/O, nlll ,
.................................. 95
8.13 Byte inputloutput
.......................... 95
8.13.1 get-bytel2, get-bytell
....................... 96
8.13.2 peek-bytel2, peek-bytell
......................... 97
8.13.3 put-bytel2, put-bytell
.................................. 98
8.14 Term inputloutput
............. 98
8.14.1 read_term/3, read_term/2, readll, readl2
8.14.2 write_term/3, write_term/2, writell, writel2, writeqll,
......... 99
writeql2, writecanonicalll, write-canonicall2
...................................... 101
8.14.3 op/3
................................ 102
8.14.4 current-op/3
............................ 103
8.14.5 char-conversionl2
....................... 103
8.14.6 currentcharconversionl2
................................. 104
8.15 Logic and control
......................... 104
8.15.1 (\+)/l - not provable
.................................... 105
8.15.2 oncell
................................... 105
8.15.3 repeat/O
............................. 105
8.16 Atomic term processing
............................... 106
8.16.1 atomJengthl2
............................... 106
8.16.2 atomconcatl3
................................. 107
8.16.3 sub-atom/5
................................
8.16.4 atomcharsl2
............................... 109
8.16.5 atomcodes
................................. 109
8.16.6 char-codel2
.............................. 110
8.16.7 numbercharsl2
.............................. 111
8.16.8 numbercodesl2
......................... 112
8.17 Implementation defined hooks
............................. 112
8.17.1 set-prologflagl2
.......................... 112
8.17.2 current-prologflagl2
..................................... 113
8.17.3 halt/0
..................................... 113
8.17.4 halt/1
.................................... 114
9 Evaluable functors
........................ 114
9.1 The simple arithmetic functors
....
...