# code-block-pro/1.27.3/build/shiki/samples/jison.sample

Code Block Pro – Beautiful Syntax Highlighting, version 1.27.3. 61 lines.

- Page: https://pluginprobe.com/plugins/code-block-pro/1.27.3/code/build/shiki/samples/jison.sample
- Raw: https://pluginprobe.com/plugins/code-block-pro/1.27.3/raw/build/shiki/samples/jison.sample
- Modified: 2023-01-28T16:44:20+00:00

Line numbers below start at 1. Link to a line or a range by appending a fragment to the
page URL, for example `https://pluginprobe.com/plugins/code-block-pro/1.27.3/code/build/shiki/samples/jison.sample#L10-L20`.

```
/* description: Parses end executes mathematical expressions. */

/* lexical grammar */
%lex

%%
\s+                   /* skip whitespace */
[0-9]+("."[0-9]+)?\b  return 'NUMBER';
"*"                   return '*';
"/"                   return '/';
"-"                   return '-';
"+"                   return '+';
"^"                   return '^';
"("                   return '(';
")"                   return ')';
"PI"                  return 'PI';
"E"                   return 'E';
<<EOF>>               return 'EOF';

/lex

/* operator associations and precedence */

%left '+' '-'
%left '*' '/'
%left '^'
%left UMINUS

%start expressions

%% /* language grammar */

expressions
    : e EOF
        {print($1); return $1;}
    ;

e
    : e '+' e
        {$$ = $1+$3;}
    | e '-' e
        {$$ = $1-$3;}
    | e '*' e
        {$$ = $1*$3;}
    | e '/' e
        {$$ = $1/$3;}
    | e '^' e
        {$$ = Math.pow($1, $3);}
    | '-' e %prec UMINUS
        {$$ = -$2;}
    | '(' e ')'
        {$$ = $2;}
    | NUMBER
        {$$ = Number(yytext);}
    | E
        {$$ = Math.E;}
    | PI
        {$$ = Math.PI;}
    ;

/* From https://gerhobbelt.github.io/jison/docs/#specifying-a-language */
```