[5.8] Parse 0.2 after … as float literal, not member access
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Deciding whether `0.2` should be lexed as a float literal or a member access is a little more difficult than just looking at the previous character because `0.2` might be preceeded by an operator like `…` or `.^.`, in which case it should be lexed as a float literal and not a member access. We might be able to do some disambiguation magic on whether the character before the period is also an operator continuation point but that seems fairly brittle to me. The sanest way of doing this, is to store the previously lexed token’s kind in the cursor and checking that. I measured and did not see a performance regregssion when parsing MovieSwiftUI. rdar://103273988
ahoppen
changed the title
0.2 after … as float literal, not member access0.2 after … as float literal, not member access
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@swift-ci Please test |
bnbarham
approved these changes
Feb 1, 2023
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Cherry-pick #1277 to
release/5.8.Deciding whether
0.2should be lexed as a float literal or a member access is a little more difficult than just looking at the previous character because0.2might be preceeded by an operator like…or.^., in which case it should be lexed as a float literal and not a member access.We might be able to do some disambiguation magic on whether the character before the period is also an operator continuation point but that seems fairly brittle to me. The sanest way of doing this, is to store the previously lexed token’s kind in the cursor and checking that.
I measured and did not see a performance regregssion when parsing MovieSwiftUI.
rdar://103273988