Expand string interpolation expressions into dedicated AST #4192
Comments
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👍. This is how I did it in the CoffeeScriptRedux compiler. |
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IIRC, that would also help out with some other tricky issues. Like the old implicit call rewriter kludge. |
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@jashkenas I think that particular issue was fixed in commit 76c076d ;) But I do agree that information is lost in many places in the parser.
Just a FYI: this is not true. But it is true that the AST looks the same. grammar.coffee:150. |
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awesomesauce! This would be super helpful |
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@juliankrispel I'm working on this (and have come very far, all tests are currently passing): https://github.com/lydell/coffee-script/tree/node-types |
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@lydell omg this is amazing. Tbh I'm not sure what I'm looking at but it's amazing nonetheless :D |
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i hope you’re looking at lydell/coffee-script@5e54fc4, which is mostly new, more specific Node classes. one of which being changes like this tell me that doing the other stuff also is a very good idea! |
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It should also fix some other long-standing bugs like |
lydell
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Previously, the parser created `Literal` nodes for many things. This resulted in information loss. Instead of being able to check the node type, we had to use regexes to tell the different types of `Literal`s apart. That was a bit like parsing literals twice: Once in the lexer, and once (or more) in the compiler. It also caused problems, such as `` `this` `` and `this` being indistinguishable (fixes jashkenas#2009). Instead returning `new Literal` in the grammar, subtypes of it are now returned instead, such as `NumberLiteral`, `StringLiteral` and `IdentifierLiteral`. `new Literal` by itself is only used to represent code chunks that fit no category. `StringWithInterpolations` has been added as a subtype of `Parens`, and `RegexWithInterpolations` as a subtype of `Call`. This makes it easier for other programs to make use of CoffeeScript's "AST" (nodes). For example, it is now possible to distinguish between `"a #{b} c"` and `"a " + b + " c"`. Fixes jashkenas#4192. Note, though, that some information is still lost, especially in the lexer. For example, there is no way to distinguish a heredoc from a regular string, or a heregex without interpolations from a regular regex. After the new subtypes were added, they were taken advantage of, removing most regexes in nodes.coffee. `SIMPLENUM` (which matches non-hex integers) had to be kept, though, because such numbers need special handling in JavaScript (for example in `1..toString()`). An especially nice hack to get rid of was using `new String()` for the token value for reserved identifiers (to be able to set a property on them which could survive through the parser). Now it's a good old regular string. In range literals, slices, splices and for loop steps when number literals are involved, CoffeeScript can do some optimizations, such as precomputing the value of, say, `5 - 3` (outputting `2` instead of `5 - 3` literally). As a side bonus, this now also works with hexadecimal number literals, such as `0x02`. Finally, this also improves the output of `coffee --nodes`: # Before: $ bin/coffee -ne 'while true "#{a}" break' Block While Value Bool Block Value Parens Block Op + Value """" Value Parens Block Value "a" "break" # After: $ bin/coffee -ne 'while true "#{a}" break' Block While Value Bool: true Block Value StringWithInterpolations Block Op + Value StringLiteral: "" Value Parens Block Value IdentifierLiteral: a StatementLiteral: break
lydell
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Previously, the parser created `Literal` nodes for many things. This resulted in information loss. Instead of being able to check the node type, we had to use regexes to tell the different types of `Literal`s apart. That was a bit like parsing literals twice: Once in the lexer, and once (or more) in the compiler. It also caused problems, such as `` `this` `` and `this` being indistinguishable (fixes jashkenas#2009). Instead returning `new Literal` in the grammar, subtypes of it are now returned instead, such as `NumberLiteral`, `StringLiteral` and `IdentifierLiteral`. `new Literal` by itself is only used to represent code chunks that fit no category. `StringWithInterpolations` has been added as a subtype of `Parens`, and `RegexWithInterpolations` as a subtype of `Call`. This makes it easier for other programs to make use of CoffeeScript's "AST" (nodes). For example, it is now possible to distinguish between `"a #{b} c"` and `"a " + b + " c"`. Fixes jashkenas#4192. Note, though, that some information is still lost, especially in the lexer. For example, there is no way to distinguish a heredoc from a regular string, or a heregex without interpolations from a regular regex. After the new subtypes were added, they were taken advantage of, removing most regexes in nodes.coffee. `SIMPLENUM` (which matches non-hex integers) had to be kept, though, because such numbers need special handling in JavaScript (for example in `1..toString()`). An especially nice hack to get rid of was using `new String()` for the token value for reserved identifiers (to be able to set a property on them which could survive through the parser). Now it's a good old regular string. In range literals, slices, splices and for loop steps when number literals are involved, CoffeeScript can do some optimizations, such as precomputing the value of, say, `5 - 3` (outputting `2` instead of `5 - 3` literally). As a side bonus, this now also works with hexadecimal number literals, such as `0x02`. Finally, this also improves the output of `coffee --nodes`: # Before: $ bin/coffee -ne 'while true "#{a}" break' Block While Value Bool Block Value Parens Block Op + Value """" Value Parens Block Value "a" "break" # After: $ bin/coffee -ne 'while true "#{a}" break' Block While Value Bool: true Block Value StringWithInterpolations Block Op + Value StringLiteral: "" Value Parens Block Value IdentifierLiteral: a StatementLiteral: break
lydell
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Previously, the parser created `Literal` nodes for many things. This resulted in information loss. Instead of being able to check the node type, we had to use regexes to tell the different types of `Literal`s apart. That was a bit like parsing literals twice: Once in the lexer, and once (or more) in the compiler. It also caused problems, such as `` `this` `` and `this` being indistinguishable (fixes jashkenas#2009). Instead returning `new Literal` in the grammar, subtypes of it are now returned instead, such as `NumberLiteral`, `StringLiteral` and `IdentifierLiteral`. `new Literal` by itself is only used to represent code chunks that fit no category. `StringWithInterpolations` has been added as a subtype of `Parens`, and `RegexWithInterpolations` as a subtype of `Call`. This makes it easier for other programs to make use of CoffeeScript's "AST" (nodes). For example, it is now possible to distinguish between `"a #{b} c"` and `"a " + b + " c"`. Fixes jashkenas#4192. `SuperCall` has been added as a subtype of `Call`. However, I didn't manage to decouple the two, so most of the `super` logic still lives in `Call`. Note, though, that some information is still lost, especially in the lexer. For example, there is no way to distinguish a heredoc from a regular string, or a heregex without interpolations from a regular regex. After the new subtypes were added, they were taken advantage of, removing most regexes in nodes.coffee. `SIMPLENUM` (which matches non-hex integers) had to be kept, though, because such numbers need special handling in JavaScript (for example in `1..toString()`). An especially nice hack to get rid of was using `new String()` for the token value for reserved identifiers (to be able to set a property on them which could survive through the parser). Now it's a good old regular string. In range literals, slices, splices and for loop steps when number literals are involved, CoffeeScript can do some optimizations, such as precomputing the value of, say, `5 - 3` (outputting `2` instead of `5 - 3` literally). As a side bonus, this now also works with hexadecimal number literals, such as `0x02`. Finally, this also improves the output of `coffee --nodes`: # Before: $ bin/coffee -ne 'while true "#{a}" break' Block While Value Bool Block Value Parens Block Op + Value """" Value Parens Block Value "a" "break" # After: $ bin/coffee -ne 'while true "#{a}" break' Block While Value Bool: true Block Value StringWithInterpolations Block Op + Value StringLiteral: "" Value Parens Block Value IdentifierLiteral: a StatementLiteral: break
lydell
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Previously, the parser created `Literal` nodes for many things. This resulted in information loss. Instead of being able to check the node type, we had to use regexes to tell the different types of `Literal`s apart. That was a bit like parsing literals twice: Once in the lexer, and once (or more) in the compiler. It also caused problems, such as `` `this` `` and `this` being indistinguishable (fixes jashkenas#2009). Instead returning `new Literal` in the grammar, subtypes of it are now returned instead, such as `NumberLiteral`, `StringLiteral` and `IdentifierLiteral`. `new Literal` by itself is only used to represent code chunks that fit no category. `StringWithInterpolations` has been added as a subtype of `Parens`, and `RegexWithInterpolations` as a subtype of `Call`. This makes it easier for other programs to make use of CoffeeScript's "AST" (nodes). For example, it is now possible to distinguish between `"a #{b} c"` and `"a " + b + " c"`. Fixes jashkenas#4192. `SuperCall` has been added as a subtype of `Call`. However, I didn't manage to decouple the two, so most of the `super` logic still lives in `Call`. Note, though, that some information is still lost, especially in the lexer. For example, there is no way to distinguish a heredoc from a regular string, or a heregex without interpolations from a regular regex. After the new subtypes were added, they were taken advantage of, removing most regexes in nodes.coffee. `SIMPLENUM` (which matches non-hex integers) had to be kept, though, because such numbers need special handling in JavaScript (for example in `1..toString()`). An especially nice hack to get rid of was using `new String()` for the token value for reserved identifiers (to be able to set a property on them which could survive through the parser). Now it's a good old regular string. In range literals, slices, splices and for loop steps when number literals are involved, CoffeeScript can do some optimizations, such as precomputing the value of, say, `5 - 3` (outputting `2` instead of `5 - 3` literally). As a side bonus, this now also works with hexadecimal number literals, such as `0x02`. Finally, this also improves the output of `coffee --nodes`: # Before: $ bin/coffee -ne 'while true "#{a}" break' Block While Value Bool Block Value Parens Block Op + Value """" Value Parens Block Value "a" "break" # After: $ bin/coffee -ne 'while true "#{a}" break' Block While Value Bool: true Block Value StringWithInterpolations Block Op + Value StringLiteral: "" Value Parens Block Value IdentifierLiteral: a StatementLiteral: break
lydell
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Feb 9, 2016
Previously, the parser created `Literal` nodes for many things. This resulted in information loss. Instead of being able to check the node type, we had to use regexes to tell the different types of `Literal`s apart. That was a bit like parsing literals twice: Once in the lexer, and once (or more) in the compiler. It also caused problems, such as `` `this` `` and `this` being indistinguishable (fixes jashkenas#2009). Instead returning `new Literal` in the grammar, subtypes of it are now returned instead, such as `NumberLiteral`, `StringLiteral` and `IdentifierLiteral`. `new Literal` by itself is only used to represent code chunks that fit no category. `StringWithInterpolations` has been added as a subtype of `Parens`, and `RegexWithInterpolations` as a subtype of `Call`. This makes it easier for other programs to make use of CoffeeScript's "AST" (nodes). For example, it is now possible to distinguish between `"a #{b} c"` and `"a " + b + " c"`. Fixes jashkenas#4192. `SuperCall` has been added as a subtype of `Call`. Note, though, that some information is still lost, especially in the lexer. For example, there is no way to distinguish a heredoc from a regular string, or a heregex without interpolations from a regular regex. After the new subtypes were added, they were taken advantage of, removing most regexes in nodes.coffee. `SIMPLENUM` (which matches non-hex integers) had to be kept, though, because such numbers need special handling in JavaScript (for example in `1..toString()`). An especially nice hack to get rid of was using `new String()` for the token value for reserved identifiers (to be able to set a property on them which could survive through the parser). Now it's a good old regular string. In range literals, slices, splices and for loop steps when number literals are involved, CoffeeScript can do some optimizations, such as precomputing the value of, say, `5 - 3` (outputting `2` instead of `5 - 3` literally). As a side bonus, this now also works with hexadecimal number literals, such as `0x02`. Finally, this also improves the output of `coffee --nodes`: # Before: $ bin/coffee -ne 'while true "#{a}" break' Block While Value Bool Block Value Parens Block Op + Value """" Value Parens Block Value "a" "break" # After: $ bin/coffee -ne 'while true "#{a}" break' Block While Value Bool: true Block Value StringWithInterpolations Block Op + Value StringLiteral: "" Value Parens Block Value IdentifierLiteral: a StatementLiteral: break
lydell
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Previously, the parser created `Literal` nodes for many things. This resulted in information loss. Instead of being able to check the node type, we had to use regexes to tell the different types of `Literal`s apart. That was a bit like parsing literals twice: Once in the lexer, and once (or more) in the compiler. It also caused problems, such as `` `this` `` and `this` being indistinguishable (fixes jashkenas#2009). Instead returning `new Literal` in the grammar, subtypes of it are now returned instead, such as `NumberLiteral`, `StringLiteral` and `IdentifierLiteral`. `new Literal` by itself is only used to represent code chunks that fit no category. `StringWithInterpolations` has been added as a subtype of `Parens`, and `RegexWithInterpolations` as a subtype of `Call`. This makes it easier for other programs to make use of CoffeeScript's "AST" (nodes). For example, it is now possible to distinguish between `"a #{b} c"` and `"a " + b + " c"`. Fixes jashkenas#4192. `SuperCall` has been added as a subtype of `Call`. Note, though, that some information is still lost, especially in the lexer. For example, there is no way to distinguish a heredoc from a regular string, or a heregex without interpolations from a regular regex. After the new subtypes were added, they were taken advantage of, removing most regexes in nodes.coffee. `SIMPLENUM` (which matches non-hex integers) had to be kept, though, because such numbers need special handling in JavaScript (for example in `1..toString()`). An especially nice hack to get rid of was using `new String()` for the token value for reserved identifiers (to be able to set a property on them which could survive through the parser). Now it's a good old regular string. In range literals, slices, splices and for loop steps when number literals are involved, CoffeeScript can do some optimizations, such as precomputing the value of, say, `5 - 3` (outputting `2` instead of `5 - 3` literally). As a side bonus, this now also works with hexadecimal number literals, such as `0x02`. Finally, this also improves the output of `coffee --nodes`: # Before: $ bin/coffee -ne 'while true "#{a}" break' Block While Value Bool Block Value Parens Block Op + Value """" Value Parens Block Value "a" "break" # After: $ bin/coffee -ne 'while true "#{a}" break' Block While Value BooleanLiteral: true Block Value StringWithInterpolations Block Op + Value StringLiteral: "" Value Parens Block Value IdentifierLiteral: a StatementLiteral: break
lydell
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Previously, the parser created `Literal` nodes for many things. This resulted in information loss. Instead of being able to check the node type, we had to use regexes to tell the different types of `Literal`s apart. That was a bit like parsing literals twice: Once in the lexer, and once (or more) in the compiler. It also caused problems, such as `` `this` `` and `this` being indistinguishable (fixes jashkenas#2009). Instead returning `new Literal` in the grammar, subtypes of it are now returned instead, such as `NumberLiteral`, `StringLiteral` and `IdentifierLiteral`. `new Literal` by itself is only used to represent code chunks that fit no category. (While mentioning `NumberLiteral`, there's also `InfinityLiteral` now, which is a subtype of `NumberLiteral`.) `StringWithInterpolations` has been added as a subtype of `Parens`, and `RegexWithInterpolations` as a subtype of `Call`. This makes it easier for other programs to make use of CoffeeScript's "AST" (nodes). For example, it is now possible to distinguish between `"a #{b} c"` and `"a " + b + " c"`. Fixes jashkenas#4192. `SuperCall` has been added as a subtype of `Call`. Note, though, that some information is still lost, especially in the lexer. For example, there is no way to distinguish a heredoc from a regular string, or a heregex without interpolations from a regular regex. Binary and octal number literals are indistinguishable from hexadecimal literals. After the new subtypes were added, they were taken advantage of, removing most regexes in nodes.coffee. `SIMPLENUM` (which matches non-hex integers) had to be kept, though, because such numbers need special handling in JavaScript (for example in `1..toString()`). An especially nice hack to get rid of was using `new String()` for the token value for reserved identifiers (to be able to set a property on them which could survive through the parser). Now it's a good old regular string. In range literals, slices, splices and for loop steps when number literals are involved, CoffeeScript can do some optimizations, such as precomputing the value of, say, `5 - 3` (outputting `2` instead of `5 - 3` literally). As a side bonus, this now also works with hexadecimal number literals, such as `0x02`. Finally, this also improves the output of `coffee --nodes`: # Before: $ bin/coffee -ne 'while true "#{a}" break' Block While Value Bool Block Value Parens Block Op + Value """" Value Parens Block Value "a" "break" # After: $ bin/coffee -ne 'while true "#{a}" break' Block While Value BooleanLiteral: true Block Value StringWithInterpolations Block Op + Value StringLiteral: "" Value Parens Block Value IdentifierLiteral: a StatementLiteral: break
lydell
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Mar 5, 2016
Previously, the parser created `Literal` nodes for many things. This resulted in information loss. Instead of being able to check the node type, we had to use regexes to tell the different types of `Literal`s apart. That was a bit like parsing literals twice: Once in the lexer, and once (or more) in the compiler. It also caused problems, such as `` `this` `` and `this` being indistinguishable (fixes jashkenas#2009). Instead returning `new Literal` in the grammar, subtypes of it are now returned instead, such as `NumberLiteral`, `StringLiteral` and `IdentifierLiteral`. `new Literal` by itself is only used to represent code chunks that fit no category. (While mentioning `NumberLiteral`, there's also `InfinityLiteral` now, which is a subtype of `NumberLiteral`.) `StringWithInterpolations` has been added as a subtype of `Parens`, and `RegexWithInterpolations` as a subtype of `Call`. This makes it easier for other programs to make use of CoffeeScript's "AST" (nodes). For example, it is now possible to distinguish between `"a #{b} c"` and `"a " + b + " c"`. Fixes jashkenas#4192. `SuperCall` has been added as a subtype of `Call`. Note, though, that some information is still lost, especially in the lexer. For example, there is no way to distinguish a heredoc from a regular string, or a heregex without interpolations from a regular regex. Binary and octal number literals are indistinguishable from hexadecimal literals. After the new subtypes were added, they were taken advantage of, removing most regexes in nodes.coffee. `SIMPLENUM` (which matches non-hex integers) had to be kept, though, because such numbers need special handling in JavaScript (for example in `1..toString()`). An especially nice hack to get rid of was using `new String()` for the token value for reserved identifiers (to be able to set a property on them which could survive through the parser). Now it's a good old regular string. In range literals, slices, splices and for loop steps when number literals are involved, CoffeeScript can do some optimizations, such as precomputing the value of, say, `5 - 3` (outputting `2` instead of `5 - 3` literally). As a side bonus, this now also works with hexadecimal number literals, such as `0x02`. Finally, this also improves the output of `coffee --nodes`: # Before: $ bin/coffee -ne 'while true "#{a}" break' Block While Value Bool Block Value Parens Block Op + Value """" Value Parens Block Value "a" "break" # After: $ bin/coffee -ne 'while true "#{a}" break' Block While Value BooleanLiteral: true Block Value StringWithInterpolations Block Op + Value StringLiteral: "" Value Parens Block Value IdentifierLiteral: a StatementLiteral: break
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Hi, as seen in #3831, string interpolation like
"A #{a} B #{b}"is lexed as if it was'A '+a+' B '+b.as mentioned in juliankrispel/decaf#2, there are use cases for having the semantic information survive lexing.
Therefore it would be awesome if we could introduce a new
StringInterpolationAST node which is later converted to a concatenation expression.The text was updated successfully, but these errors were encountered: