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我正在尝试在这个版本的项目中实现错误恢复（make然后./parse e1.input进行测试）。

鉴于(1，e1.input我希望解析器表现得好像它已解析)并构建了一个 AST Paren (Int 1)。因此，我尝试了

let (startp, endp) = positions in
let _ = feed (T T_RPAREN) startp () endp env in

但是，它返回了一个错误Invalid_argument("feed: outgoing transition does not exist")

hahahaha depth of env 2
hahahaha current_state_number 2
hahahaha startp 1:1
hahahaha endp   1:2

element number of state 2
element startp 1:1
element endp   1:2
element incoming_symbol an integer
element v toComplete
element item: an expression -> an integer.

element number of state 1
element startp 1:0
element endp   1:1
element incoming_symbol (
element v toComplete
element item: an expression -> ( .an expression )

Line 1, characters 2-2: Error (parsing)
  Error while analyzing an expression.
Fatal error: exception Invalid_argument("feed: outgoing transition does not exist")

有谁知道为什么会出现这个错误？

4

1 回答 1

0

在喂食之前)，我们应该先减少，以下代码有效：

let env_new = force_reduction (find_production 1) env in
let env_new_new = feed (T T_RPAREN) startp () endp env_new in
(lex, input_needed env_new_new)

例如(1+2，我们应该在喂食之前减少两次)，以下代码有效：

let env_new = force_reduction (find_production 1) env in
let env_new_new = force_reduction (find_production 3) env_new in
let env_new_new_new = feed (T T_RPAREN) startp () endp env_new_new in
(lex, input_needed env_new_new_new)
于 2022-03-04T15:20:24.140 回答