

Built-in Procedures

KEY

2.1  Input / Output
     2.1.1  Reading in Programs
     2.1.2  File Handling
     2.1.3  Input and Output of Terms
     2.1.4  Character Input/Output
2.2  Editing files and calling Emas Commands
2.3  Arithmetic
2.4  Convenience
2.5  Extra Control
2.6  Meta-Logical
2.7  Modification of the Program
2.8  Information about the State of the Program
2.9  Collecting together solutions
2.10  Internal Database
2.11  Debugging
2.12  Environmental
2.13  Pre-Processing


Built-in procedures are also referred to as evaluable predicates.
This  section  describes  all the built-in predicates available in EMAS Prolog.
These predicates are provided in advance by  the  system  and  they  cannot  be
redefined by the user.  If you try to add clauses for a built-in predicate then
this  will cause an error, and the built-in predicates will be unaffected.  The
EMAS Prolog system provides a fairly  wide  range  of  built-in  predicates  to
perform the following tasks:

    Input/Output
            Reading-in programs
            Opening and closing files
            Reading and writing Prolog terms
            Getting and putting characters
    Editing files and calling Emas commands
    Arithmetic
    Affecting the flow of the execution
    Classifying and operating on Prolog terms (meta-logical facilities)
    Manipulating the Prolog program database
    Manipulating the additional indexed database
    Debugging facilities
    Environmental facilities

The  following  descriptions  of  the built-in predicates will follow the above
categorisation of their tasks. In Appendix II there is a complete list  of  the
built-in predicates.