Expression.Evaluate

Expression

Evaluates a Power Query M expression provided as text at runtime.

Syntax

Expression.Evaluate(document as text, optional environment as nullable record) as any

Parameters

Name	Type	Required	Description
`document`	`text`	Yes	The M expression text to evaluate.
`environment`	`record`	No	A record of names and values available to the expression during evaluation.

Return Value

any — The result of evaluating the M expression.

Remarks

Expression.Evaluate compiles and executes an M expression provided as a text string. This enables dynamic or meta-programming scenarios where the expression to run is not known at design time.

The environment parameter is critical — it defines which names (functions, values, types) are available inside the evaluated expression. Without an environment, the expression has access only to built-in constants and operators. To make standard library functions available, pass #shared as the environment:

``powerquery Expression.Evaluate("Text.Upper(""hello"")", #shared)``

Or pass a custom environment with specific bindings:

``powerquery Expression.Evaluate("x + y", [x = 10, y = 20])``

### Important notes

- The evaluated expression runs in an isolated scope. It cannot access let bindings or step names from the surrounding query unless you explicitly pass them in the environment record. - #shared provides access to all standard library functions and any other queries in the workbook. - Use this sparingly — dynamic evaluation can make queries harder to debug and may prevent query folding.

Examples

Example 1: Evaluate a simple arithmetic expression

let
    Result = Expression.Evaluate("a * b + c", [a = 5, b = 4, c = 3])
in
    #table({"Expression", "Result"}, {{"a * b + c  (a=5, b=4, c=3)", Result}})

Result

	Expression	Result
1	a * b + c (a=5, b=4, c=3)	23

Example 2: Evaluate with standard library functions

let
    Result = Expression.Evaluate("Text.Reverse(""Power Query"")", #shared)
in
    #table({"Input", "Reversed"}, {{"Power Query", Result}})