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Closes #1483 The error now points to the offending `=`, works correctly with multi-line clauses, and explains exactly what's wrong. E.g. for ```agda f : Nat → Nat → Nat; f zero x = x; ``` we get ``` | 6 | f zero x = x; | ^ expected ":=" instead of "=" ``` A minor disadvantage of the proposed solution is that now it's impossible to use `=` without parentheses as a top variable name in a pattern, e.g. ``` f zero = := =; ``` gives an error. However, if one really wants to name a variable `=`, it is enough just to enclose it in parentheses: ```agda f : Nat → Nat → Nat; f zero (=) := =; f (suc n) (=) := f n =; ``` I believe this slight non-uniformity is well worth the increased usability due to a better error message. Confusing `:=` with `=` is very common. Using `=` as a variable name in a top pattern is rare. Co-authored-by: janmasrovira <janmasrovira@gmail.com>
37 lines
590 B
Plaintext
37 lines
590 B
Plaintext
module Symbols;
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open import Stdlib.Data.Nat;
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╘⑽╛ : Nat;
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╘⑽╛ := suc nine;
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-- no - function!?
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- : Nat -> Nat -> Nat;
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- := (+);
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（-） : Nat -> Nat -> Nat;
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（-） := (-);
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（*） : Nat -> Nat -> Nat;
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（*） := (*);
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infixl 6 －;
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－ : Nat -> Nat -> Nat;
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－ := （-）;
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infixl 7 ·;
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· : Nat -> Nat -> Nat;
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· := （*）;
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（0） : Nat;
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（0） := ╘⑽╛ － ╘⑽╛ · zero;
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主功能 : Nat;
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主功能 := （0）;
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axiom = : Type;
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K : Nat → Nat → Nat;
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K =a@zero (=) := =a · =;
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K =a@(suc =) == := = · ==;
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end;
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