Databases
StackOverflow2013
Postsdbo
POANTLR Grammar for expressions
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POANTLR Grammar for expressions
    primarykey
    data
    text
    <p>I'm trying to implement a expression handling grammar (that deals with nested parenthesis and stuff). I have the following so far, but they can't deal with some cases (successful/failure cases appear after the following code block). Anyone know what's going on?</p> <p>Note: The <em>varname +=</em> and <em>varname =</em> stuff are just some additional AST generation helper stuff in XText. Don't worry about them for now.</p> <pre><code>... NilExpression returns Expression: 'nil'; FalseExpression returns Expression: 'false'; TrueExpression returns Expression: 'true'; NumberExpression returns Expression: value=Number; StringExpression returns Expression: value=STRING; //EllipsesExpression: '...'; //FunctionExpression: function=function; //don't allow random functions UnaryExpression: op=unop ('(' expr=Expression ')')|expr=Expression; BinaryExpression: 'or'? AndOp; //or op AndOp: 'and'? ComparisonOp; ComparisonOp: ('&gt;'|'&lt;'|'&gt;='|'&lt;='|'=='|'~=')? ConcatOp; ConcatOp: '..'? AddSubOp; AddSubOp: ('+' '-')? MultDivOp; MultDivOp: ('*' '/')? ExpOp; ExpOp: '^'? (('(' expr=Expression ')')|expr=Expression); ExprSideOne : Variable|NilExpression|FalseExpression|TrueExpression| NumberExpression|StringExpression|UnaryExpression; Expression: ( '(' expression1=ExprSideOne expression2+=BinaryExpression* ')' ) | ( expression1=ExprSideOne expression2+=BinaryExpression* ) ; ... </code></pre> <p>And here's the list of parses/fails:</p> <pre><code>c = ((b)); //fails c = ((a not b)); //fails c = b; //parses d = (b); //parses </code></pre>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USjameszhao00
    1. USjameszhao00
    plurals
    1. This table or related slice is empty.
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    3. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POANTLR Grammar for expressions
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POANTLR Grammar for expressions
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POANTLR Grammar for expressions
      1. This table or related slice is empty.
      1. VTUpMod
    1. CONeed recursion. Just out of curiosity, why are your binary operator rules written as unary operators? Is nil >= .. + * (1) supposed to mean something?
      singulars
      1. POANTLR Grammar for expressions
      1. USEllery Newcomer
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload