libPPF - Programmable Property Files
Property files are used to associate keys with values. A value can be looked up using the key.
Programmable Property Files are useful when there is a high correlation between the values of the properties that needs to be defined.
Each line in a property file defines one or more properties using regular expressions and TCL expressions.
<regexp1> <regexp2> ... <regexpN> = <TCL expression>
First, one or more regular expressions defines the property key that must match when the property is looked up. After the '=' sign is a TCL expression that is used to calculate the value of the property.
The variables $1, $2 to $N are bound to the strings that matches each regular expression.
weight 0 = weightless weight [1-3] = [expr $2 / 2.0]g
will represent the properties:
weight 0 = weightless weight 1 = 0.5g weight 2 = 1g weight 3 = 1.5g
libPPF - PPF C++ API
libPPF is an implementation of a PPF API in C++. It consists of three classes, ppf::Parser, ppf::BoundBundle and ppf::Bundle. The latter is not part of the public API.
The API organizes the properties in a tree hierarchy, where BoundBundle represents a node, and which may have properties as leafs.
#include "ppf/parser.h" using namespace ppf; Parser parser; BoundBundle root = parser.parse("properties.ppf"); BoundBundle weight = root.getBoundBundle("weight"); string value = weight.getProperty("2");
The parser object must be kept in memory during the time the root bundle and its children are used, because it manages the memory for the parsed data.