Rich set of keywords supported by ysh / Wysh

The inference engine, YSH (pronounced 'why-shell') uses a natural language knowledge representation. Knowledge may be represented as backward or forward chaining rules, or procedures, or any combinations of these, for the purposes of rule-based inferencing.

Rule types

• RULE
• GOAL
• PROCEDURE
• BACKWARD
• FORWARD
• DAEMON
• DOCUMENT
• EXAMPLE
• LISTED

Attribute types

• BOOLEAN
• INTEGER
• REAL
• DOLLAR
• SEX
• STRING
• DATE

Document types

(For documents only)

• PARAGRAPH
• LINE
• TEXT

Name subject types

• PERSON
• PERSONTHING
• THING

Translation operators

• TRANSLATE - AS
• PROMPT

Statement operators

• ASSERT
• DETERMINE
• IF - THEN - ELSE
• ONLY IF
• IS
• WHILE - DO
• REPEAT - UNTIL
• CALL
• BEGIN - END

Expression operators

(Pre) Unary operators

• NOT
• MINUS
• PLUS
• DAY
• MONTH
• YEAR

(Post) Unary operators

• DAYS
• WEEKS
• MONTHS
• YEARS

Binary operators (1)

• DIVIDED BY
• TIMES
• PLUS
• MINUS

Binary operators (2)

• IN
• EQUALS
• NOT EQUALS
• IS GREATER THAN
• IS LESS THAN
• IS GREATEREQUAL THAN
• IS LESSEQUAL THAN

Binary operators (3)

• AND/OR
• AND/OR/WITH
• AND
• AND/WITH
• OR
• OR/WITH

Layout operators

(For documents only)

• NUMBERED
• LEVEL

Misc operators

• RANGE - TO
• VERBS
• PROVIDES
• ORDER