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Hello, gopy

hello.py
print("Hello, gopy")
$ gopy hello.py
Hello, gopy

What just happened​

  1. Parse. parser.ParseFile reads hello.py, runs the tokenizer, and runs the PEG parser. The result is an AST: a single Module node containing one Expr statement that wraps a Call to a Name print with the string "Hello, gopy" as its argument.

  2. Compile. compile.Compile runs the symbol-table builder on the AST, then the code generator, then the flow-graph optimiser, then the assembler. The output is a Code object.

  3. Run. pythonrun.Run hands the code object to the VM. The VM creates a frame, pushes it, and enters the dispatch loop.

  4. Print. LOAD_NAME finds print in the builtins module. LOAD_CONST pushes the string. CALL invokes print, which writes to sys.stdout. RETURN_VALUE pops the frame.

Disassembly​

The compiler emits the bytecode below. The -d flag is parsed but not yet wired in gopy; for now, the easiest way to inspect gopy's output is to run python3 -m dis hello.py under CPython 3.14. gopy's bytecode is identical:

  0           0 RESUME                   0

  1           2 LOAD_NAME                0 (print)
              4 PUSH_NULL
              6 LOAD_CONST               0 ('Hello, gopy')
              8 CALL                     1
             16 POP_TOP
             18 RETURN_CONST             1 (None)

See Debugging for the introspection surface that gopy does ship today.

Where to go from here​

The Run a file page documents every shape of invocation. The CLI page documents every flag. To learn how the four stages above work, jump to the CPython internals pipeline overview and read down. The gopy pillar mirrors each page on the CPython side with the Go implementation.