grammer.jison

%lex
%%

\s+                   /* skip whitespace */
"fun"                 return 'FUN'
[0-9]+                return 'INT'
"=>"                  return '=>'
<<EOF>>               return 'EOF'
.                     return 'INVALID'

/lex

%nonassoc FUNEXP
%left APPLY

%start expressions

%%

expressions
    : e EOF
        { return $1; }
    ;

e
    : e e %prec APPLY
        {$$ = ['APPLY', $1, $2];}
    | FUN var '=>' e %prec FUNEXP
        {$$ = ['FUN', $2, $4];}
    ;

xerror

Conflict in grammar: multiple actions possible when lookahead token is FUN in state 5
- reduce by rule: e -> e e
- shift token (then go to state 3)
Conflict in grammar: multiple actions possible when lookahead token is FUN in state 8
- reduce by rule: e -> FUN var => e
- shift token (then go to state 3)

States with conflicts:
State 5
  e -> e e . #lookaheads= EOF FUN
  e -> e .e
  e -> .e e
  e -> .FUN var => e
State 8
  e -> FUN var => e . #lookaheads= EOF FUN
  e -> e .e
  e -> .e e
  e -> .FUN var => e