How to bring up a REPL?

[philderbeast]

Please show how to bring up a REPL in the tutorial. From #380 it looks like I might be able to run a -repl target to do this.

The command to run as shown now in the readme;

rules_haskell_examples> bazel run @tutorial//main:demorgan
INFO: Analysed target @tutorial//main:demorgan (1 packages loaded).
INFO: Found 1 target...
Target @tutorial//main:demorgan up-to-date:
  bazel-bin/external/tutorial/main/demorgan
INFO: Elapsed time: 1.573s, Critical Path: 1.41s
INFO: 5 processes: 5 darwin-sandbox.
INFO: Build completed successfully, 9 total actions
INFO: Build completed successfully, 9 total actions
True

From the root folder, trying to run the -repl target;

rules_haskell_examples> bazel run @tutorial//main:demorgan-repl
INFO: Analysed target @tutorial//main:demorgan-repl (0 packages loaded).
INFO: Found 1 target...
Target @tutorial//main:demorgan-repl up-to-date:
  bazel-bin/external/tutorial/main/demorgan-repl
INFO: Elapsed time: 0.157s, Critical Path: 0.04s
INFO: 1 process: 1 darwin-sandbox.
INFO: Build completed successfully, 4 total actions
INFO: Build completed successfully, 4 total actions
GHCi, version 8.2.2: http://www.haskell.org/ghc/  :? for help
Loaded GHCi configuration from /Users/pdejoux/.ghci

<no location info>: error:
    can't find file: external/tutorial/main/Main.hs
Failed, no modules loaded.

<no location info>: error:
    Could not find module ‘Main’
    It is not a module in the current program, or in any known package.
Loaded GHCi configuration from bazel-out/darwin-fastbuild/bin/external/tutorial/main/ghci-repl-script-demorgan
Prelude> :q
Leaving GHCi.

From the tutorial folder, trying to run the -repl target;

rules_haskell_examples> cd tutorial
tutorial> bazel run //main:demorgan-repl
INFO: Analysed target //main:demorgan-repl (1 packages loaded).
INFO: Found 1 target...
Target //main:demorgan-repl up-to-date:
  bazel-bin/main/demorgan-repl
INFO: Elapsed time: 0.226s, Critical Path: 0.04s
INFO: 1 process: 1 darwin-sandbox.
INFO: Build completed successfully, 4 total actions
INFO: Build completed successfully, 4 total actions
GHCi, version 8.2.2: http://www.haskell.org/ghc/  :? for help
Loaded GHCi configuration from /Users/pdejoux/.ghci
[1 of 1] Compiling Main             ( main/Main.hs, interpreted )

main/Main.hs:5:1: error:
    Could not find module ‘Bool’
    Perhaps you haven't installed the "dyn" libraries for package ‘booleans-1.0.0’?
    Use -v to see a list of the files searched for.
  |
5 | import Bool
  | ^^^^^^^^^^^
Failed, no modules loaded.

<no location info>: error:
    Could not find module ‘Main’
    It is not a module in the current program, or in any known package.
Loaded GHCi configuration from bazel-out/darwin-fastbuild/bin/main/ghci-repl-script-demorgan
Prelude> :q
Leaving GHCi.

[mboes]

Your latter command session works for me on Linux. Perhaps this is a Darwin specific problem. @judah seen this before?

[judah]

The latter command failed for me with bazel-0.16.2 on Mac OS High Sierra, though with a different error:

GHCi, version 8.2.2: http://www.haskell.org/ghc/  :? for help
ghc: can't find a package database at bazel-out/darwin-fastbuild/bin/external/tutorial/lib/externalZStutorialZSlibZSbooleans-1.0.0

[judah]

@mboes does it work for you even after a "clean"?

$ bazel clean
$ bazel build @tutorial//main:demorgan-repl
...
INFO: Build completed successfully, 5 total actions
$ ls bazel-bin/external/tutorial/lib/
ls: bazel-bin/external/tutorial/lib/: No such file or directory
$ bazel build @tutorial//main:demorgan
...
INFO: Build completed successfully, 19 total actions
$ ls bazel-bin/external/tutorial/lib/
externalZStutorialZSlibZSbooleans-1.0.0
interfaces-booleans
libHSexternalZStutorialZSlibZSbooleans-1.0.0-ghc8.2.2.dylib
libHSexternalZStutorialZSlibZSbooleans-1.0.0-ghc8.2.2.dylib.temp
libHSexternalZStutorialZSlibZSbooleans-1.0.0.a
objects-booleans
registration-file-booleans

Do you get similar output, or do you get the "lib" outputs still built from the repl too on Linux?

[mboes]

@judah same behaviour as you. -repl only works if we build first. How nasty.

[mboes]

There seem to be two bugs here. I do likewise get the same output as @philderbeast's second command session in the description.

[Profpatsch]

-repl only works if we build first. How nasty.

That should be fixed once we switch the repl code to runfiles (#348).

[mboes]

@Profpatsch ok so is there anything left here to do that isn't a dupe of #348?

[Profpatsch]

Actually all of that should be fixed by #736, according to Andreas.