Advanced Candid argument operations

[nmattia]

Currently (AFAICT) I can only pass full-fledged arguments to dfx install, e.g.:

$ dfx canister install --argument '(record {foo="bar"})'

I would like dfx to be able to read a (CLI) argument and splice it in for me, so that I don't have to deal with any shell escaping madness:

$ dfx canister install --value bar baz --argument '(record {foo=$bar})'
# install argument expands to '(record {foo="baz"})'

See for instance the various options e.g. jq offers for setting arguments/values:

$ jq --help
...
  --arg a v        set variable $a to value <v>;
  --argjson a v    set variable $a to JSON value <v>;
  --slurpfile a f  set variable $a to an array of JSON texts read from <f>;
  --rawfile a f    set variable $a to a string consisting of the contents of <f>;

[ericswanson-dfinity]

The example above has --value foo bar on the command-line, seemingly identifying the field name foo and the variable name bar, but not the variable value.

First question: would this be a better example?

$ dfx canister install --value bar baz --argument '(record {foo=$bar})'
# install argument expands to '(record {foo="baz"})'

[nmattia]

Yes, thanks! Edited