Parse-statement
Parse a statement.
- Signature
(parse-statement parstate) → (mv erp stmt span new-parstate)
- Arguments
- parstate — Guard (parstatep parstate).
- Returns
- stmt — Type (stmtp stmt).
- span — Type (spanp span).
- new-parstate — Type (parstatep new-parstate), given (parstatep parstate).
Most statements start with distinct keywords or punctuators
(one punctuator, the open curly brace),
but both labeled statements and expression statements
may start with an identifier.
However, for a labeled statement,
the token after the identifier is a colon,
which cannot be an expression.
So we are able to distinguish all kinds of statements
based on the first one or two tokens.
The well-known dangling-else grammatical ambiguity is dealt with
by associating the else with the closest if,
as required in [C:6.8.4/3].
There is a syntactic overlap between the two kinds of for loops,
the one with an expression and the one with a declaration.
An identifier may be a declaration specifier
or (the start of) an expression.
For now we handle the situation approximately:
if the token there may start an expresison,
we commit to parsing an expression;
otherwise we parse a declaration.
In other words, we may fail to accept the case of
a declaration that starts with a typedef name for now.
We plan to rectify this situation soon.
