SpringDataПостроительПарсер

peg-parser.txt

// See https://pegjs.org/online
// Sample expressions:
//   FindBy${Name}
//   FindFirstBy${Name}
//   FindBy${Name}And${OperationType}OrderBy${Name}And${OperationType}DescCount

Query "query"
  = s:Start t:Transform* f:Finalizer?
    { return {start: s, transforms: t, finalizer: f} }

Start "start"
  = FindBy

Transform "transform"
  = OrderBy

Finalizer "finalizer"
 = 'Count' { return {op: 'COUNT'} }

FindBy "findBy"
  = 'Find' finder:('First' / 'All')? 'By' e: Expression
      { return {op: 'FIND', finder: finder, expression: e} }
  
Expression "expr"
  = head:SimpleExpr tail:('And' e: SimpleExpr { return e })*
      { return {type: 'AND', args: [head, ...tail]} }

SimpleExpr "simpleExpr"
  = field:FieldName operation:('Contains' / 'StartsWith' / 'Between')?
      { return {type: 'field', fieldName: field, operation: operation} }

FieldName "fieldName"
  = '${' name:([^}]+ { return text() }) '}' { return name }

OrderBy "orderBy"
  = 'OrderBy' head:FieldCollation
    tail:('And' field: FieldCollation { return field })* {
    return {op: 'orderBy', columns: [head, ...tail]}
  }

FieldCollation "fieldCollation"
  = field:FieldName dir:SortDir? { return {field: field, dir: dir} }

SortDir "sortDir"
  = 'Asc' / 'Desc'

sample-output.js

// FindBy${Name}And${OperationType}OrderBy${Name}And${OperationType}DescCount
{
   "start": {
      "op": "FIND",
      "finder": null,
      "expression": {
         "type": "AND",
         "args": [
            {
               "type": "field",
               "fieldName": "Name",
               "operation": null
            },
            {
               "type": "field",
               "fieldName": "OperationType",
               "operation": null
            }
         ]
      }
   },
   "transforms": [
      {
         "op": "orderBy",
         "columns": [
            {
               "field": "Name",
               "dir": null
            },
            {
               "field": "OperationType",
               "dir": "Desc"
            }
         ]
      }
   ],
   "finalizer": {
      "op": "COUNT"
   }
}