The rationale here is the same as the last commit: since this crate
exclusively parses SQL, there's no need to restate that in every type
name. (The prefix seems to be an artifact of this crate's history as a
submodule of Datafusion, where it was useful to explicitly call out
which types were related to SQL parsing.)
This commit has the additional benefit of making all type names
consistent; over type we'd added some types which were not prefixed with
"SQL".
The ASTNode enum was confusingly named. In the past, the name made
sense, as the enum contained nearly all of the nodes in the AST, but
over time, pieces have been split into different structs, like
SQLStatement and SQLQuery. The ASTNode enum now contains only contains
expression nodes, so Expr is a better name.
Also rename the UnnamedExpression and ExpressionWithAlias variants
of SQLSelectItem to UnnamedExpr and ExprWithAlias, respectively, to
match the new shorthand for the word "expression".
Standardize the license header, removing the Grove Enterprise copyright
notice where it exists per #58. Also add a CI check to ensure that files
without license headers don't get merged.
Fix#58.
The `@@version` test is MS' dialect of SQL, it seems, so test it with
its own dialect.
Update the rules for identifiers in Postresql dialect per documentation,
while we're at it. The current identifier rules in Postgresql dialect
were introduced in this commit - as a copy of generic rules, it seems:
810cd8e6cf (diff-2808df0fba0aed85f9d35c167bd6a5f1L138)
