Elm simple elastic query

This package allow to parse an elastic simple query string into an AST.

~N tokenizer is not supported.

At this time, the default operator for elastic must be set to "AND" in elastic search services.

Alphabet

• ( ) Group
• [WORD] Char+
• | OR
• + AND
• -- Exclude
• "" Exact
• * prefix search
• Specific case : Spaces (signifying in some contexts and not in others)

AST

type AST
  = And AST AST
  | Or AST AST
  | Exclude AST
  | Exact String
  | Word String
  | Prefix String

In our case, to follow the production rules AST will be Expr

type Expr
    = And Expr Expr
    | Exact String
    | Exclude Expr
    | Or Expr Expr
    | Prefix String
    | Word String

Production rules

Unless explicitly indicated, spaces are ignored.

Query => ORExpr EOF
ORExpr => ANDExpr | ANDExpr "|" ORExpr
ANDExpr => EXCExpr | EXCExpr ("+"|\s+) ANDExpr
EXCExpr => "-" GRPExpr | GRPExpr
GRPExpr => WORD~"\*" | WORD | \" EXACTExpr \" | "(" ORExpr ")"
EXACTExpr => [^"]+

Example of simple query String

big* (potatoes|"french fries") -salad