Runtime evaluation

Runtime evaluation
You are encouraged to solve this task according to the task description, using any language you may know.

Demonstrate your language's ability for programs to execute other programs in the language provided at runtime. Show us how you get values in and out (e.g. environments, arguments, return values), and what facilities for restricting (e.g. sandboxes, resource limits) or specializing (e.g. debugging facilities) the execution.

You may not invoke a separate evaluator program, or invoke a compiler and then its output, unless the interface of that program, and the syntax and means of executing it, are considered part of your language/library/platform.

For a more restricted task, see Eval in environment.

Common Lisp

Using a list to represent code

<lang lisp>(eval '(+ 4 5)) ; Evaluate the program (+ 4 5)</lang>

Using a String to represent code

<lang lisp>(eval (read-from-string "(+ 4 5)")) ; Evaluate the program (+ 4 5)</lang>

Groovy

This program evaluates the Groovy program solution to the "Yuletide Holiday" task: <lang Groovy> new GroovyShell().evaluate inFormat = new java.text.SimpleDateFormat("yyyy-MM-dd") checkFormat = new java.text.SimpleDateFormat("EEE")

result = [] (2008..2121).each {

   Date date = inFormat.parse("${it}-12-25")
   if (checkFormat.format(date) == "Sun") result.add it

}

print result </lang>

Output:

[2011, 2016, 2022, 2033, 2039, 2044, 2050, 2061, 2067, 2072, 2078, 2089, 2095, 2101, 2107, 2112, 2118]

Perl

<lang perl>eval '4 + 5'</lang>

Smalltalk

<lang smalltalk> [ 4 + 5 ] value.</lang>

Tcl

<lang tcl> eval "expr {4 + 5}"  ;# string input

eval [list expr [list 4 + 5]] ;# list input </lang>