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3 commits

Author SHA1 Message Date
Timothy Flynn
6efbafa6e0 Everywhere: Update copyrights with my new serenityos.org e-mail :^) 2022-01-31 18:23:22 +00:00
Jan de Visser
5c4890411b LibSQL: Make lexer and parser more standard SQL compliant
SQL was standardized before there was consensus on sane language syntax
constructs had evolved. The language is mostly case-insensitive, with
unquoted text converted to upper case. Identifiers can include lower
case characters and other 'special' characters by enclosing the
identifier with double quotes. A double quote is escaped by doubling it.
Likewise, a single quote in a literal string is escaped by doubling it.

All this means that the strategy used in the lexer, where a token's
value is a StringView 'window' on the source string, does not work,
because the value needs to be massaged before being handed to the
parser. Therefore a token now has a String containing its value. Given
the limited lifetime of a token, this is acceptable overhead.

Not doing this means that for example quote removal and double quote
escaping would need to be done in the parser or in AST node
construction, which would spread lexing basically all over the place.
Which would be suboptimal.

There was some impact on the sql utility and SyntaxHighlighter component
which was addressed by storing the token's end position together with
the start position in order to properly highlight it.

Finally, reviewing the tests for parsing numeric literals revealed an
inconsistency in which tokens we accept or reject: `1a` is accepted but
`1e` is rejected. Related to this is the fate of `0x`. Added a FIXME
reminding us to address this.
2021-06-24 00:36:53 +02:00
Jan de Visser
4198f7e1af LibSQL: Move Lexer and Parser machinery to AST directory
The SQL engine is expected to be a fairly sizeable piece of software.
Therefore we're starting to restructure the codebase for growth.
2021-06-24 00:36:53 +02:00
Renamed from Userland/Libraries/LibSQL/Lexer.cpp (Browse further)