compile

Learn to turn AST into executable code with compile().

What is compile?

compile turns an AST or a code string into an executable code object. It takes three arguments: source, filename and mode ("exec", "eval" or "single").

Mode "exec" runs multiple statements; "eval" evaluates a single expression. You run the resulting code object with exec or eval. Transforming an AST and recompiling it is a powerful technique for code generation and macro-like tools.

From AST to code object

You compile an AST with compile(tree, "<test>", "exec"). The second argument is the filename; it shows up in error messages, usually a name like "<test>". The third is the mode.

You run the resulting code object with exec(code, ns) in a namespace. The ns dict holds variables; you access them with ns["result"]. This flow — parse, transform, compile, run — is the classic chain of code-processing tools. It is flexible because each step is separately controllable.

Exercise Run an AST with compile

Import the module with import ast. Build the tree with ast.parse("sonuc = 6 * 7"). Produce a code object with compile(tree, "<test>", "exec"). Run exec(code, ns) in an ns = {} dict and print ns["sonuc"].

Show example solution

import ast

tree = ast.parse("sonuc = 6 * 7")
code = compile(tree, "<test>", "exec")
ns = {}
exec(code, ns)
print(ns["sonuc"])

Test yourself

Match compile concepts

compile

Turns into code
exec

Multiple statements
eval

Single expression
code object

Executable

Complete the compile call

code = ____(tree, "<test>", "exec")

Show answer

code = compile(tree, "<test>", "exec")

What does compile mode 'exec' do?
```
code = compile("x = 1
y = 2", "<t>", "exec")
ns = {}
exec(code, ns)
print(ns)
```
- Raises an error
- Runs multiple statements
- Evaluates one expression
- Returns only a constant
Show answer

Runs multiple statements — 'exec' mode runs multiple statements; 'eval' is for a single expression.

Next lesson: Summary - AST

We Are Enhancing Your Experience

Cookie Preferences

Strictly Necessary Cookies

Analytical Cookies