Changes between Version 5 and Version 6 of ScopedTypeVariables


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Timestamp:
Dec 6, 2005 12:26:00 AM (8 years ago)
Author:
john@…
Comment:

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  • ScopedTypeVariables

    v5 v6  
    3939  * A rule like ExplicitQuantification would most likely be needed if these were put into the standard. 
    4040  
     41== Proposal 1 == 
     42 
     43both pattern bound and let type signature bound variables are in scope in the 
     44body of a function. only let type signature bound variables may shadow other 
     45variables and no variables are ever in scope in a let type signature, pattern 
     46bound variables do not shadow but rather refer to the same type. 
     47ExplicitQuantification is required for all expression type signatures but not 
     48let type signatures. 
     49 
     50This proposal tries to strike a balance between backwards compatability, 
     51avoiding accidental type errors, and simplicity. let type signatures always 
     52create a new scope, pattern bound ones are always in the same scope and 
     53it is clear from expression type signatures what is a scoped type var.