Package dev.cel.expr

Class Expr.Comprehension

  • All Implemented Interfaces:
    Message, MessageLite, MessageLiteOrBuilder, MessageOrBuilder, Expr.ComprehensionOrBuilder, java.io.Serializable
    Enclosing class:
    Expr
    public static final class Expr.Comprehension
extends GeneratedMessageV3
implements Expr.ComprehensionOrBuilder
     A comprehension expression applied to a list or map.
 Comprehensions are not part of the core syntax, but enabled with macros.
 A macro matches a specific call signature within a parsed AST and replaces
 the call with an alternate AST block. Macro expansion happens at parse
 time.
 The following macros are supported within CEL:
 Aggregate type macros may be applied to all elements in a list or all keys
 in a map:
 *  `all`, `exists`, `exists_one` -  test a predicate expression against
    the inputs and return `true` if the predicate is satisfied for all,
    any, or only one value `list.all(x, x < 10)`.
 *  `filter` - test a predicate expression against the inputs and return
    the subset of elements which satisfy the predicate:
    `payments.filter(p, p > 1000)`.
 *  `map` - apply an expression to all elements in the input and return the
    output aggregate type: `[1, 2, 3].map(i, i * i)`.
 The `has(m.x)` macro tests whether the property `x` is present in struct
 `m`. The semantics of this macro depend on the type of `m`. For proto2
 messages `has(m.x)` is defined as 'defined, but not set`. For proto3, the
 macro tests whether the property is set to its default. For map and struct
 types, the macro tests whether the property `x` is defined on `m`.
 Comprehension evaluation can be best visualized as the following
 pseudocode:
 ```
 let `accu_var` = `accu_init`
 for (let `iter_var` in `iter_range`) {
   if (!`loop_condition`) {
     break
   }
   `accu_var` = `loop_step`
 }
 return `result`
 ```
    Protobuf type cel.expr.Expr.Comprehension
    See Also:
    Serialized Form