README.md

Upgrade scripts for 0.7

Invocation

This tool fixes Elvishscript code written before 0.7. It can be invoked in one of two ways:

• Without arguments, it reads stdin and writes stdout.

• With filename arguments, it rewrites each given file.

It does not accept any flags.

Scope of this tool

This tool fixes the syntax part of all breaking changes when upgrading from 0.6 to 0.7. For a comprehensive list, see the notes for the 0.7 pre-release.

Note that since control structures now introduce their own scopes, variables defined within them are no longer accessible outside. For instance, this used to work:

if true; then
  x = 1
else
  x = 2
fi
put $x $x

After automatic fixing, the above becomes the following, which does not work:

if (true) {
  x = 1
} else {
  x = 2
}
put $x $x

To fix this, either declare $x beforehand:

x = ''
if (true) {
  x = 1
} else {
  x = 2
}
put $x $x

Or rewrite the code like this:

x = (
  if (true) {
    put 1
  } else {
    put 2
  })
put $x $x

Assignment syntax

This tool does one more thing. Version 0.6 introduced a more readable syntax for assignment, allowing spaces around the equal sign: for instance, this program will fix a=b to a = b. The new syntax does not support doing multiple assignments at once, so a=b c=d will be split into two commands: a = b; c = d.

Note that the old syntax is not going away though: it is still the syntax for temporary assignments, so a=b ls will be left untouched. Support for using this syntax for non-temporary assignments will be dropped in a later version.