1.0.0-alpha.13 Pipeline operator and build improvements

Pipeline operator

This release introduces pipeline operator | (vertical bar), that can be used to chain queries:

foo.bar | size() + baz.smth() | qux

It needed to simplify making subquery for a query. For example, if we need to get a subquery size() + bar.smth() from a foo.bar, we may express it as foo.bar | size() + bar.smth() which means the same as (foo.bar).(size() + bar.smth()).

However, this operator is much useful when a query value needs to be converted to a scalar. For example, we need to produce an object from an array. We can't use mapping for that, i.e. [1,2,3].({ sum: sum(), size: size() }), since it will map each element of array to an object. A single possible workaround is to use a variable:

$ar: [1,2,3]; { sum: $ar.sum(), size: $ar.size() }

It works, but using the pipeline operator we may avoid any variables:

[1,2,3] | { sum: sum(), size: size() }

It also can be used to simplify expressions avoiding mapping:

{ foo: ..., bar: ... }.(foo + bar)
// ->
{ foo: ..., bar: ... } | foo + bar

or reduce repetitions:

$a.bar + $a.baz
// ->
$a | bar + baz

Pipeline operator produces a regular query, so it may be used in any place where a query is applicable, e.g.

query.({
   foo: $ | { ... },
   baz: $baz | a + b
}) | foo * bar

Is't also possible to define variables on pipeline chunk (except first one), right after |:

query | $a: expr1; $b: expr2; $a.foo + bar.[baz=$b]

All changes

• Added pipeline operator, i.e. foo | bar | ...
• Added fromEntries() method
• Allowed parent's scope variables overlapping, i.e. $a;.($a; ...) doesn't throw with an error now
• Added support for a function as debug option value, i.e. query('...', { debug: (name, value) => /* ... */ })
• Disallowed whitespace between $ and identifier, previously $foo can be used as $ foo, now it throws with a parse error
• Reworked build setup:
  • Added baking of src/parser.js before publishing, i.e. replace a runtime parser compilation with a pre-compiled version
  • Moved jison to dev dependencies, and package has no dependencies anymore (dev only)
  • Removed dist/parser.js & dist/version.json from package