CODEWITHSUNDEEP
pythonebnflark-parser
Asustor
Asustor

Reputation: 21

How to extract a string according to rule of python lark ebnf?

I would like to parse the following PlantUML which likes flow-charts, by using python lark package. The syntax of each action is based on verilog-hdl.

PlantUML

@startuml
:[7:0] a;
:write(reg01, 8'h01, );

if (flag == 1'b1) then (Yes)
  :write(reg01, 8'h01, );
endif
@enduml

When parse uml with the following ebnf, the following error occored at 2nd function call.

EBNF

start: "@startuml" (statement | cond_if)* "@enduml"

cond_if: "if" "(" condition ")" "then" "(" "Yes" ")" (statement)* "endif"

statement: ":" expression ";"
condition: expression
expression: /[^;\n]+/

%import common.WS
%ignore WS

Error

Error: No terminal matches ':' in the current parser context, at line 6 col 3

  :write(reg01, 8'h01, );
  ^
Expected one of:
        * RPAR

I copied the line of function call :write(reg01, 8'h01, ); to outside of if branch (like line 3). Then, 1st function call (outside of if branch) is OK but 2nd (inside of if branch) is NG.

I would like to extract write(reg01, 8'h01, ) as one token of expression because expression will be parsed by other parser.

How do I modify EBNF?

Upvotes: 1

Views: 48

Answers (0)

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