Association of properties to definitions
The input for a text processor usually describes objects that have certain
properties, e.g. named entities like variables in a program, or fields of
a data base. Their properties are determined, used, or checked according
to the context in which an object occurs. An object may occur several times
in the input. The occurrences are mapped to a unique identification,
a key (see Name Analysis Library of Name analysis according to scope rules). Properties are associated and accessed
via those keys. Properties are represented by values of certain types.
The Eli tool PDL is used to generate functions that
store property values in a data base of the language processor and that
retrieve values from it.
The modules of this library can solve a large variety of tasks.
OccCnt module enumerates occurrences of each
object. Its result can be used to check whether an identifier
is multiply defined. It can also be used to trigger an output
operation exactly once for each object. Such an output
may say how often the identifier occurs in the text, or
it may be a declaration of the identifier in the target code.
The first section describes how the modules are instatiated and used,
the others describe the modules contained in this library: