# Exclusion and inclusion filters

Exclusion and inclusion filters are Ant file patterns that further define the set of source files to be considered by the Tcl builder and other tools. To allow nesting of source folders inside each other, or simply to exclude parts of a source tree, one can associate exclusion filters to a source folder. Symmetrically inclusion filters can be used to include another part of a source tree. The Tcl builder will ignore source files that are excluded, and the ones that are not included.