CelExpr.CelComprehension

java.lang.Object
- dev.cel.common.ast.CelExpr.CelComprehension

Enclosing class:

CelExpr
```
@Immutable
public abstract static class CelExpr.CelComprehension
extends java.lang.Object
```
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:

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class CelExpr.CelComprehension.Builder
Builder for Comprehension.

Constructor Summary

Constructors
Constructor Description

CelComprehension()

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`abstract CelExpr`	`accuInit()`	The initial value of the accumulator.
`abstract java.lang.String`	`accuVar()`	The name of the variable used for accumulation of the result.
`abstract CelExpr`	`iterRange()`	The range over which var iterates.
`abstract java.lang.String`	`iterVar()`	The name of the iteration variable.
`abstract CelExpr`	`loopCondition()`	An expression which can contain iter_var and accu_var.
`abstract CelExpr`	`loopStep()`	An expression which can contain iter_var and accu_var.
`static CelExpr.CelComprehension.Builder`	`newBuilder()`
`abstract CelExpr`	`result()`	An expression which can contain accu_var.
`abstract CelExpr.CelComprehension.Builder`	`toBuilder()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - CelComprehension
```
public CelComprehension()
```
- Method Detail
  - iterVar
```
public abstract java.lang.String iterVar()
```
    The name of the iteration variable.
  - iterRange
```
public abstract CelExpr iterRange()
```
    The range over which var iterates.
  - accuVar
```
public abstract java.lang.String accuVar()
```
    The name of the variable used for accumulation of the result.
  - accuInit
```
public abstract CelExpr accuInit()
```
    The initial value of the accumulator.
  - loopCondition
```
public abstract CelExpr loopCondition()
```
    An expression which can contain iter_var and accu_var.
    Returns false when the result has been computed and may be used as a hint to short-circuit the remainder of the comprehension.
  - loopStep
```
public abstract CelExpr loopStep()
```
    An expression which can contain iter_var and accu_var.
    Computes the next value of accu_var.
  - result
```
public abstract CelExpr result()
```
    An expression which can contain accu_var.
    Computes the result.
  - toBuilder
```
public abstract CelExpr.CelComprehension.Builder toBuilder()
```
  - newBuilder
```
public static CelExpr.CelComprehension.Builder newBuilder()
```