12.13 Phase and Space Utilities

The racket/phase+space library provides functions for manipulating combined representations of phase levels and binding spaces, particularly as used for require transformers and provide transformers.

When identifier-binding (and related functions, like identifier-transformer-binding), syntax-local-module-exports, syntax-local-module-required-identifiers, module-compiled-exports, or module->exports produces a phase–space combination (or phase–space shift combination), then two such values that are equal? will be eqv?.

Added in version 8.2.0.3 of package base.

• a phase (in the sense of phase?) by itself, which represents that phase plus the default binding space

• a pair whose car is a phase and whose cdr is a non-#f space (in the sense of space?)

• exact integer — represents an amount to shift a phase level and no change to the binding space

• #f — represents a shift to the label phase level and no change to the binding space

• a pair whose car is an exact integer or #f, and whose cdr is a space (in the sense of space?) — represents a phase level shift in the car and a change to the binding space that is in the cdr