The repl package provides a read/eval/print loop for Skylark.
It supports readline-style command editing, and interrupts through Control-C.
If an input line can be parsed as an expression, the REPL parses and evaluates it and prints its result. Otherwise the REPL reads lines until a blank line, then tries again to parse the multi-line input as an expression. If the input still cannot be parsed as an expression, the REPL parses and executes it as a file (a list of statements), for side effects.
MakeLoad returns a simple sequential implementation of module loading suitable for use in the REPL. Each function returned by MakeLoad accesses a distinct private cache.
PrintError prints the error to stderr, or its backtrace if it is a Skylark evaluation error.
REPL executes a read, eval, print loop.
Before evaluating each expression, it sets the Skylark thread local variable named "context" to a context.Context that is cancelled by a SIGINT (Control-C). Client-supplied global functions may use this context to make long-running operations interruptable.