parsing - Erlang ** exception error: no function clause matching -
hi guys have makings of parser theorem prover. have module tokenises string im inputting: [{bracket,open},{prop,a},{logicop,'and'},{prop,b},{bracket,close}] parser has calls inner function. here code:
parse([])-> []; parse(fulllist) -> parseclauses(fulllist,[],[]). parseclauses([{bracket, open}| restoflist], stacklist, parsedlist) -> parseclauses(restoflist, stacklist ++ [{bracket, open}], parsedlist); parseclauses([{prop, any},{logicop, any}| restoflist], stacklist, parsedlist) -> parseclauses(restoflist, stacklist ++ [{logicop, any},{prop, any}], parsedlist); parseclauses([{bracket, close}, {logicop, any}| restoflist],stacklist,parsedlist) -> parseclauses(restoflist, stacklist ++ [{bracket, close}], [{logicop, any}] ++ parsedlist); parseclauses([{bracket, close}|restoflist], stacklist, parsedlist) -> parseclauses(restoflist, stacklist++[{bracket, close}], parsedlist); parseclauses([], stack, parsed) -> parsed ++ stack. run code on terminal , error:
tokeniser:parse([{bracket,open}, {prop,a}, {logicop,'and'}, {prop,b}, {bracket,close}]). ** exception error: no function clause matching tokeniser:parseclauses([{prop,a},{logicop,'and'},{prop,b},{bracket,close}], [{bracket,open}], [])
from error message, can tell function being called this:
tokeniser:parseclauses([{prop,a},{logicop,'and'},{prop,b},{bracket,close}], [{bracket,open}], []) this almost matches clause:
parseclauses([{prop, any},{logicop, any}| restoflist], stacklist, parsedlist) -> but since any used twice in argument list, clause matches when 2 values same. in call, different: a , 'and'.
you change 2 occurences of any else, e.g. prop , logicop, , clause accept 2 different values.
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