GHCi: Behave nicely on `-e`, like `ghc` and other programs

Andrew Pennebaker andrew.pennebaker at
Wed Jul 23 23:29:26 UTC 2014

Like many programming language environments, GHC offers a handy `-e` option
for evaluating an expression, then returning to the shell.

$ ghc -e '2 + 2'


One would expect the interpreter, GHCi, to offer a similar flag, but it
surprisingly rejects it.

ghci -e '2 + 2'

ghc: on the commandline: cannot use `--interactive' with `-e'

Usage: For basic information, try the `--help' option.

I think this behavior is quite unintuitive--when I pass `-e <exp>` to ghci,
or pass `--interactive -e <exp>` to ghc, I expect the expression to be
evaluated as the leading expression in an interactive interpreter session.

Could we please tweak ghc like this to make it slightly more intuitive when
these flags are used together?

Andrew Pennebaker
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