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Sounds nice in theory. But how is syntax based version control ever supposed to work when we have so many languages that literally parse differently depending

Sounds nice in theory. But how is syntax based version control ever supposed to work when we have so many languages that literally parse differently depending on dependencies that aren't even in the codebase? Let alone ones that easily take hours to compile even when they are in the codebase? Sounds impossible in practice unless we restrict ourselves to sufficiently context free languages.

int0x80 5y ago
Do you have an example of a language that parses different because of dependencies?
- dataflow 5y ago
  Sure, just plain C can wreck any kind of parsing with its macros.
  - int0x80 5y ago
    Technically the parsing itself and the grammar are the same, they don't depend on defined macros. Yes, defining a macro in an included file can make the resulting AST change, but the parsing algorithm doesn't really care about it.
  - chriswarbo 5y ago
    Unfortunately, text-substitution macros (like CPP) pretty much force a source file to be treated as a stream of bytes. They can be handy, but delimited macros (e.g. like Lisps) are much less invasive.
    - dataflow 5y ago
      Yeah that's kind of my point. The idea of syntax based source control is nice in theory but in reality it's just wishful thinking with the kinds of languages we use.
- layer8 5y ago
  Languages with user-defined operators with user-defined precedence, like Haskell. Languages with user-defined subgrammars, like Raku (Perl 6). Languages with declaration-dependent ambiguity resolution, like C++ (https://en.wikipedia.org/wiki/Most_vexing_parse https://en.wikipedia.org/wiki/Most_vexing_parse).
kazinator 5y ago
> But how is syntax based version control ever supposed to work when we have so many languages that literally parse differently depending on dependencies that aren't even in the codebase? You create a language geared toward syntax-based version control which doesn't do that, and then relegate syntax-based version control the ghetto based around that language (not offering it as a general-purpose tool for programming in anything).

int0x80 5y ago

Do you have an example of a language that parses different because of dependencies?

dataflow 5y ago
Sure, just plain C can wreck any kind of parsing with its macros.
- int0x80 5y ago
  Technically the parsing itself and the grammar are the same, they don't depend on defined macros. Yes, defining a macro in an included file can make the resulting AST change, but the parsing algorithm doesn't really care about it.
- chriswarbo 5y ago
  Unfortunately, text-substitution macros (like CPP) pretty much force a source file to be treated as a stream of bytes. They can be handy, but delimited macros (e.g. like Lisps) are much less invasive.
  - dataflow 5y ago
    Yeah that's kind of my point. The idea of syntax based source control is nice in theory but in reality it's just wishful thinking with the kinds of languages we use.
layer8 5y ago
Languages with user-defined operators with user-defined precedence, like Haskell. Languages with user-defined subgrammars, like Raku (Perl 6). Languages with declaration-dependent ambiguity resolution, like C++ (https://en.wikipedia.org/wiki/Most_vexing_parse https://en.wikipedia.org/wiki/Most_vexing_parse).

kazinator 5y ago

> But how is syntax based version control ever supposed to work when we have so many languages that literally parse differently depending on dependencies that aren't even in the codebase? You create a language geared toward syntax-based version control which doesn't do that, and then relegate syntax-based version control the ghetto based around that language (not offering it as a general-purpose tool for programming in anything).