"use" directive

In addition to the language syntax, SML# supports 'use' directive.

Environment variables in 'use' declaration.

String argument of 'use' directive can include references to environment variables.

# use "foo_${OS}/bar.sml";

If the environment variable "OS" is "Windows", this path is interpreted as "foo_Windows/bar.sml".

File path resolution

After substitution of environment variable, the string argument is resolved to a file path by the resolution rule described in File path resolution