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"Expression" (Interpreter Type)

Wolfram Language expression.

Details

  • "Expression" can be used in Interpreter and related constructs, including deployed smart form fields.
  • Use of "Expression" does not require connectivity to the Wolfram Cloud.

Allowed Forms

  • Any valid Wolfram Language expression.

Restriction Specifications

Interpretation

Examples

Basic Examples  (7)

Interpret expressions:

Wolfram Language code: Interpreter["Expression"]["3+2"]
Wolfram Language code: Interpreter["Expression"]["Sin[Pi/2]"]

Restrict to a list of choices:

Wolfram Language code: Interpreter[Restricted["Expression", {{1, 2, 3}}]][{"4/2", "2+1", "1", "2*3"}]

By default, only expressions with no side effect are allowed:

Wolfram Language code: Interpreter["Expression"]["f[x_] := x+2"] f[1]

This can be changed by allowing All symbols:

Wolfram Language code: Interpreter[Restricted["Expression", All]]["f[x_] := x+2"] f[1]

Restrict to a list of symbols:

Wolfram Language code: Interpreter[Restricted["Expression", {Map, List, Function, Slot}]]["#&/@{1,2,3}"]
Wolfram Language code: Interpreter[Restricted["Expression", {Map, List, Function, Slot}]]["#+1&/@{1,2,3}"]

By default, new symbols are created in $Context, but a custom context can be specified:

Wolfram Language code: var = Interpreter[Restricted["Expression", Automatic, Automatic, Automatic]]["x"] Context[Evaluate[var]]
Wolfram Language code: var = Interpreter[Restricted["Expression", Automatic, Automatic, "mycontext`"]]["x"] Context[Evaluate[var]]

Specify contexts for the allowed and output symbols:

Wolfram Language code: Global`x = 10; Interpreter[Restricted["Expression", Automatic, {"Global`", "System`"}, "Global`"]]["y = x + 1"]

Prevent the creation of any new symbol:

Wolfram Language code: Interpreter[Restricted["Expression", Automatic, Automatic, None]]["3+1"]
Wolfram Language code: Interpreter[Restricted["Expression", Automatic, Automatic, None]]["z+1"]