michaelmacinnis/escape

Toy to demonstrate escape as a built-in.

Adding Escape Hatches to Go

Installing

# Install the check and escape binaries used by generate.sh.
go install ./...

# (Optional) move expand-escape to a directory in your PATH.

Running

# From the root directory of a package that uses escape() in .ego files.
expand-escape && go build

Translation

Escape looks for lines that look like,

abort := escape(&err)

or,

check := f(escape(&err))

in .ego files, and rewrites them (saving the result to a .go file) so that the function returned by escape can be used to trigger an early return from the function that called escape.

Only short variable declarations and escape() used as an argument are currently expanded.

Restrictions

The function returned by escape can only be called by a function with a call chain rooted at the function that called escape. When other uses are detected they are reported as errors.