Issue #195: Documentation: price entries are no longer automatically synthesized (blais/beancount)

[Ethan Glasser-Camp]

New issue 195: Documentation: price entries are no longer automatically synthesized
https://bitbucket.org/blais/beancount/issues/195/documentation-price-entries-are-no-longer

Ethan Glasser-Camp:

The Beancount Language Syntax page (https://docs.google.com/document/d/1wAMVrKIA2qtRGmoVDSUBJGmYZSygUaR0uOMW1GV3YE0/) includes the following remark:


```
#!

Every time a Posting appears that has a cost or
an optional price declared, it uses that cost or
price to automatically synthesize a Price directive.
For example, this transaction:

2014-05-23 *
Assets:Investments:MSFT -10 MSFT {43.40 USD}
Assets:Investments:Cash 434.00 USD

automatically becomes this after parsing:

2014-05-23 *
Assets:Investments:MSFT -10 MSFT {43.40 USD}
Assets:Investments:Cash 434.00 USD

2014-05-23 price MSFT 43.40 USD
```

However, this seems not to be true out-of-the-box. This beancount file:

```
2017-01-01 open Assets:MyBank:Cash USD
2017-01-01 open Assets:MyBank:DJIA DJIA
2017-01-01 open Equity:Opening-Balances

2017-01-01 * "Initial balance"
Assets:MyBank:Cash 10 USD
Equity:Opening-Balances

2017-03-01 * "Bought some DJIA"
Assets:MyBank:DJIA 1 DJIA {1 USD}
Assets:MyBank:Cash
```

combined with this query:

```
bean-report ~/Documents/prices.beancount all_prices
```

does not report any prices. It seems from looking through the documentation that the implicit_prices plugin is meant for this use case. Activating the implicit_prices plugin causes a price entry to appear in the report as expected. Perhaps the documentation should be amended to suggest the use of this plugin to generate these price entries. Similarly, the Trading With Beancount document at https://docs.google.com/document/d/1WjARst_cSxNE-Lq6JnJ5CC41T3WndEsiMw4d46r2694/edit#heading=h.rssekxnidtcf refers to the synthesis of a price entry based on a price in a posting, and should maybe refer interested users to the plugin.