On 27 May 2017 9:27:29 am AEST, Dennis Raddle <dennis.raddle@gmail.com> wrote:
A year ago I tried to install stack on my MacBook. Just recently I tried again, and it asked me if I wanted to upgrade rather than install. I did so, but got an error (some message from GHC saying 'the thing that should never happen, happened' or something like that). So I thought, okay let me try uninstalling stack first, then installing it, and going from there.

So I did that, and I'm working the stack tutorial, and upon doing "stack setup" I got a parse error in config.yaml.

   "Error in $.params: failed to parse field 'params', expected Map k a, encountered String"

As far as the question of where I got my config.yaml from, I edited something that was there to add some specific information, but I am not sure if I changed anything else. Here is the config.yaml that produces the above error:

# This file contains default non-project-specific settings for 'stack', used
# in all projects.  For more information about stack's configuration, see
# http://docs.haskellstack.org/en/stable/yaml_configuration/

# The following parameters are used by "stack new" to automatically fill fields
# in the cabal config. We recommend uncommenting them and filling them out if
# you intend to use 'stack new'.
# See https://docs.haskellstack.org/en/stable/yaml_configuration/#templates
templates:
  params:
    author-name:Dennis
    author-email:dennisraddle@gmail.com
    category:programming
    copyright:2017
    github-username:Dennis


Hi Dennis,

The problem is just that the structure of your YAML config file is off, so it doesn't say what you think it says.

Where you have things like "author-name:Dennis" you need a space after the colon for YAML to interpret it as a key value pair in a map. With what you have currently, the whole contents of your "params" section is just one string split over several lines, rather than a map (which is more or less what the error message is reporting).

You can see how YAML interprets your file here: https://yaml-online-parser.appspot.com/

-- Ben