DMN17 — Iteration context not allowed in quantified expressions

Currently, the grammar allows to use iteration context only in case of the for loop. However, quantified expressions (some, every) are very similar in their nature, so there is no good reason for inconcistency there. This leads to overly verbose expressions, e.g.

some i in (for j in 1..10 return j) satisfies i > 5

. One cannot simply write

some i in 1..10 satisfies i > 5

.

Allow iteration context in quantified expressions

Allow iteration context in quantified expressions, e.g. an expression like

some i in (for j in 1..10 return j) satisfies j > 5

can be shortened to

some i in 1..10 satisfies i > 5

To implement this, expression in grammar rule 46 can be replaced with iteration context, which is backwards compatible because it includes a single expression in its grammar definition:

63.iteration context = expression, [ “..”, expression ];