Refactor Lexer to support an abstract InputSource class #1363
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Nice job. My only reservation with this (apart from CohenArthur's raw pointer bit above) would be the potential performance hit of indirection for the input source. Since there's now a virtual call to get every new character in the lexer, the extra vtable lookups as a result could actually have a noticeable effect on overall performance. A template-based approach as mentioned in #1000 would avoid this performance hit at the cost of a somewhat more complicated program, slower compilation time, possibly larger generated binaries, and worse error messages on compile. I could be wrong about how much performance loss actually occurs if something else during lexing and parsing (e.g. I/O) has a much greater effect than the virtual calls, however. |
This patch allows us to remove the fmemopen lex_string hack to support parsing buffers. This will allow us to support mutliple sources such as metadata imports etc. The patch here updates the parser to hold onto a reference to the lexer rather than 'owning' the lexer which allows us to decouple the move semantics here. Fixes #1203 #1000
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bors r+ |
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Build succeeded: |
This patch allows us to remove the fmemopen lex_string hack to support
parsing buffers. This will allow us to support mutliple sources such as
metadata imports etc. The patch here updates the parser to hold onto a
reference to the lexer rather than 'owning' the lexer which allows us to
decouple the move semantics here.
Fixes #1203
Fixes #1000