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add helpers to emit result and empty

This commit is contained in:
Sean Sube 2022-09-28 21:31:34 -05:00
parent beecbff936
commit 9a0c106b6f
1 changed files with 31 additions and 25 deletions
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56
Parse.agda
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@ -25,19 +25,26 @@ record Result (A : Set) : Set where
res : Maybe A
rem : List Char
emit↓ : {A : Set} → A → List Char → Result A
emit↓ a rem = emit (just a) rem
emit↑ : {A : Set} → List Char → Result A
emit↑ rem = emit nothing rem
showResult : {A : Set} → (A → String) → Result A → String
showResult f (emit (just r) _) = primStringAppend "result: " (f r)
showResult f (emit nothing rem) = primStringAppend "remainder: " (primStringFromList rem)
showResult f (emit (just r) []) = primStringAppend "result: " (f r)
showResult f (emit (just r) xs) = primStringAppend (primStringAppend "result: " (f r)) (primStringAppend ", remainder: " (primStringFromList xs))
-- take consecutive occurences of a character set
takeCons : List Char → List Char → Result (List Char)
takeCons [] r = emit nothing r
takeCons _ [] = emit nothing []
takeCons _ [] = emit↑ []
takeCons [] r = emit↑ r
takeCons cs (x ∷ xs) with (findCharIndex 0 x cs)
... | nothing = emit nothing (x ∷ xs)
... | nothing = emit↑ (x ∷ xs)
... | just n with (takeCons cs xs)
... | emit nothing rem = emit (just (x ∷ [])) xs
... | emit (just res) rem = emit (just (x ∷ res)) rem
... | emit nothing rem = emit↓ (x ∷ []) xs
... | emit (just res) rem = emit↓ (x ∷ res) rem
digits : List Char
digits = primStringToList "0123456789"
@ -70,45 +77,44 @@ parseNat : Maybe Nat → List Char → Result Nat
parseNat a [] = emit a []
parseNat a (x ∷ xs) with parseChar x
... | Digit n = parseNat (just (((default 0 a) * 10) + n)) xs
... | Skip c = parseNat a xs
... | _ = emit nothing xs
... | _ = emit↑ xs
takeNat : List Char → Result Nat
takeNat s with takeCons digits s
... | emit nothing rem₁ = emit nothing rem₁
... | emit (just xs) rem₁ with parseNat nothing xs
... | emit nothing rem₂ = emit nothing rem₁
... | emit (just n) rem₂ = emit (just n) rem₁
... | emit nothing rem₂ = emit↑ rem₁
... | emit (just n) rem₂ = emit↓ n rem₁
takeOper : List Char → Result Token
takeOper s with takeCons opers s
... | emit nothing rem = emit nothing rem
... | emit (just []) rem = emit nothing rem
... | emit nothing rem = emit↑ rem
... | emit (just []) rem = emit↑ rem
... | emit (just (x ∷ xs)) rem with parseChar x
... | Oper o = emit (just (Oper o)) (xs ++ rem)
... | _ = emit nothing s
... | Oper o = emit↓ (Oper o) (xs ++ rem)
... | _ = emit↑ s
data BinExpr : Set where
bin : Token → Token → Token → BinExpr
evalBin : Result BinExpr → Result Nat
evalBin (emit nothing rem) = emit nothing rem
evalBin (emit (just (bin (Oper '+') (Digit a) (Digit b))) rem) = emit (just (a + b)) rem
evalBin (emit (just (bin (Oper '-') (Digit a) (Digit b))) rem) = emit (just (a - b)) rem
evalBin (emit (just (bin (Oper '*') (Digit a) (Digit b))) rem) = emit (just (a * b)) rem
evalBin (emit nothing rem) = emit↑ rem
evalBin (emit (just (bin (Oper '+') (Digit a) (Digit b))) rem) = emit↓ (a + b) rem
evalBin (emit (just (bin (Oper '-') (Digit a) (Digit b))) rem) = emit↓ (a - b) rem
evalBin (emit (just (bin (Oper '*') (Digit a) (Digit b))) rem) = emit↓ (a * b) rem
evalBin (emit (just (bin (Oper '/') (Digit a) (Digit b))) rem) with (b == zero)
... | false = emit (just (a / (suc (b - 1)))) rem -- todo: why tho
... | true = emit nothing rem
evalBin (emit (just (bin _ _ _)) rem) = emit nothing rem
... | false = emit↓ (a / (suc (b - 1))) rem -- todo: why tho
... | true = emit↑ rem
evalBin (emit (just (bin _ _ _)) rem) = emit↑ rem
takeBin : List Char → Result BinExpr
takeBin s with takeNat s
... | emit nothing rem₁ = emit nothing s
... | emit nothing rem₁ = emit↑ s
... | emit (just res₁) rem₁ with takeOper rem₁
... | emit nothing rem₂ = emit nothing rem₁
... | emit nothing rem₂ = emit↑ rem₁
... | emit (just oper) rem₂ with takeNat rem₂
... | emit nothing rem₃ = emit nothing rem₁
... | emit (just res₃) rem₃ = emit (just (bin oper (Digit res₁) (Digit res₃))) rem₃
... | emit nothing rem₃ = emit↑ rem₁
... | emit (just res₃) rem₃ = emit↓ (bin oper (Digit res₁) (Digit res₃)) rem₃
takeLine : List Char → List (Result BinExpr)
takeLine s = map takeBin (map reverse (reverse (split (';' ∷ []) s)))