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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​

gopy -d hello.py prints the bytecode the compiler produced.

  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)

This is byte-for-byte identical to what CPython 3.14 produces.

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.