Algernon Tutorial 1.f
Syntax Summary

Note: Except for symbols starting with a ':', all symbols you type in are case-sensitive. Symbols starting with a ':' will always be turned into all-uppercase symbols. Whether the KBMS is case-sensitive depends on the KBMS.

Variables

• Variables start with a question mark, e.g. ?length
• A variable acquires a type the first time it is used.
• A variable must be bound before it is used in an assertion.
• The scope of a variable is the path it is defined in.

Clause

• Generally, (relation object value)
• In a frame-based system, (slot frame value)
• In general, an unbound variable may not be used as the relation or object argument. There are exceptions for certain Algernon macros.

Path

• A path is a sequence of clauses.