Interpolation and files imported as Text

[mmhat]

Consider this a Bash script called test.sh with the following content:

#!/usr/bin/bash

cat <<EOF
echo '${1}'
EOF

Now if we run dhall <<< "./test.sh as Text" we get

''
#!/usr/bin/bash

cat <<EOF
echo '''${1}'
EOF
''

Note that '${1}' is not escaped properly. In particular dhall <<< "./test.sh as Text" | dhall errors complaining that you can only interpolate Text.

I expected that as Text imports the test.sh as raw text, i.e. without interpolation.

[Gabriella439]

@mmhat: The import is working fine (meaning that the import is being imported as raw text). If the import had not been treated as raw text then the import would have failed (because test.sh is not a valid Dhall expression).

The issue is that the '${1}' is not being escaped correctly by the pretty-printer. Normally the way to escape ${x} in a multi-line Text literal is to prefix it with two single quotes (i.e. ''${x}), but the issue is that there is already another single quote before that, leading to three single quotes in a row ('''), which is itself a separate escape sequence for two single quotes in a multi-line string literal.

Fortunately, this should be easy to fix by changing the pretty-printer to render the string to something like this:

''
#!/usr/bin/bash

cat <<EOF
echo ${"'"}''${1}'
EOF
''