New command: "run"

[adept]

Adds a new command, "run", that allows one to run hledger commands in interactive REPL or from command/script files:

#!/usr/bin/env hledger run
echo "Depth 1:"
balance assets --depth 1

echo "Depth 2:"
balance assets --depth 2

echo "Depth 3:"
balance assets --depth 3

echo "Uncategorized expenses:"
print expenses:unknown

[jokesper]

Why not use a standard bash script?

[adept]

Why not use a standard bash script?

to avoid re-parsing the same journal file (quite large, in my case) over and over and over again.

If that's not a concern, then bash script is the (better?) alternative

[simonmichael]

Why not use a standard bash script?

We can also say, for the REPL - allowing fast interactive reporting sessions without rereading the data, which could be helpful if it's large.

We had GHCI already as a REPL for the haskell API, but this one is much more like the familiar command line (though not identical).

[simonmichael]

We could also leave this as an add-on command. What might be some arguments against making it a builtin ?

• I hope in future we can speed up hledger more, perhaps with caching, which might reduce the benefit of this command a bit. It might be a temporary fix, not long term need.

• We might feel concerned about scope creep, adding complexity and dev distractions, and inventing our own custom scripting language.

Arguments for:

• Built in commands get used and improved, addons don't

• We might find some cool enhancement ideas

• Optimisation might not happen, and even if it does there's always sufficiently large data / slow machines to appreciate a speed up

• Avoiding wasted work, eg when generating scripted reports, is simply good economy of resources

• Ledger and Beancount both provide such a REPL, for similar reasons presumably, though I don't hear these REPLs discussed.

• This is extending a capability already present in hledger-ui and hledger-web, to the CLI.

• It's a step towards better support for complex/compound reports.