Parse error on double implications

[Broes De Cat]

!x: Largest(x) => Largest(x) => Largest(x). throws a parse error on the second =>

[Broes De Cat]

This is not a bug, but it would be useful to have a better warning that in fact the sentence is ambiguous without brackets.

[Bart Bogaerts]

Fixed double implications.

Double implications are now parsed as right associative, as is common in first-order logic. I updated the documentation to include this knowledge. Also added a test for this parsing. This fixes #278

→ <<cset 5dffec8f4a83>>

[Bart Bogaerts]

Fixed double implications.

Double implications are now parsed as right associative, as is common in first-order logic. I updated the documentation to include this knowledge. Also added a test for this parsing. This fixes #278

→ <<cset bc66683b3e9a>>

[Bart Bogaerts]

Fixed double implications.

Double implications are now parsed as right associative, as is common in first-order logic. I updated the documentation to include this knowledge. Also added a test for this parsing. This fixes #278

→ <<cset 5a188a32bfc7>>