Add @ entries if ledger can't do implicit conversion

[tbm]

Converting this to ledger works fine:

2020-10-23 * "Test"
    Assets:Property                   0.1 FOO {300.00 EUR}
    Assets:Property                   0.2 BAR {200.00 EUR}
    Equity:Opening-Balance

But if we change it to

2020-10-23 * "Test"
    Assets:Property                   0.1 FOO {300.00 EUR, 2020-10-22}
    Assets:Property                   0.2 BAR {200.00 EUR}
    Equity:Opening-Balance

we get:

0.2 BAR {200.000 EUR}
         -70.000 EUR
0.1 FOO {300.000 EUR} [20-Oct-22]
Amount to balance against:
0.2 BAR {200.000 EUR}
0.1 FOO {300.000 EUR} [20-Oct-22]
Error: Transaction does not balance

This is because the date make it not just EUR. (I wonder if this is a bug in ledger or not.)

I need to think about the different scenarios but it would be good to deal with this somehow.

[tbm]

The example actually works fine. You have to add -70.00 EUR to the other posting for it to fail:

2020-10-23 * "Test"
    Assets:Property                   0.1 FOO {300.00 EUR, 2020-10-22}
    Assets:Property                   0.2 BAR {200.00 EUR}
    Equity:Opening-Balance         -70.00 EUR

So this is a bit complicated because the requirement to add @ depends on a number of factors.

[tbm]

Remove the lot date and you get the same error.

[tbm]

so the question is whether ledger can do an implicit conversion or not.

[tbm]

There's actually some code that deals with this already:

              # Figure out if we need to insert a price on a posting held at cost.
              # See https://groups.google.com/d/msg/ledger-cli/35hA0Dvhom0/WX8gY_5kHy0J
...

but clearly it's not working.