2. The Very High Level Layer

Python 2.5

2. The Very High Level Layer

The functions in this chapter will let you execute Python source code given in a file or a buffer, but they will not let you interact in a more detailed way with the interpreter.

Several of these functions accept a start symbol from the grammar as a parameter. The available start symbols are Py_eval_input, Py_file_input, and Py_single_input. These are described following the functions which accept them as parameters.

Note also that several of these functions take FILE* parameters. On particular issue which needs to be handled carefully is that the FILE structure for different C libraries can be different and incompatible. Under Windows (at least), it is possible for dynamically linked extensions to actually use different libraries, so care should be taken that FILE* parameters are only passed to these functions if it is certain that they were created by the same library that the Python runtime is using.

The main program for the standard interpreter. This is made available for programs which embed Python. The argc and argv parameters should be prepared exactly as those which are passed to a C program's main() function. It is important to note that the argument list may be modified (but the contents of the strings pointed to by the argument list are not). The return value will be the integer passed to the sys.exit() function, 1 if the interpreter exits due to an exception, or 2 if the parameter list does not represent a valid Python command line.

This is a simplified interface to PyRun_AnyFileExFlags() below, leaving closeit set to 0 and flags set to NULL.

This is a simplified interface to PyRun_AnyFileExFlags() below, leaving the closeit argument set to 0.

This is a simplified interface to PyRun_AnyFileExFlags() below, leaving the flags argument set to NULL.

If fp refers to a file associated with an interactive device (console or terminal input or Unix pseudo-terminal), return the value of PyRun_InteractiveLoop(), otherwise return the result of PyRun_SimpleFile(). If filename is NULL, this function uses "???" as the filename.

This is a simplified interface to PyRun_SimpleStringFlags() below, leaving the PyCompilerFlags* argument set to NULL.

Executes the Python source code from command in the __main__ module according to the flags argument. If __main__ does not already exist, it is created. Returns 0 on success or -1 if an exception was raised. If there was an error, there is no way to get the exception information. For the meaning of flags, see below.

This is a simplified interface to PyRun_SimpleFileExFlags() below, leaving closeit set to 0 and flags set to NULL.

This is a simplified interface to PyRun_SimpleFileExFlags() below, leaving closeit set to 0.

This is a simplified interface to PyRun_SimpleFileExFlags() below, leaving flags set to NULL.

Similar to PyRun_SimpleStringFlags(), but the Python source code is read from fp instead of an in-memory string. filename should be the name of the file. If closeit is true, the file is closed before PyRun_SimpleFileExFlags returns.

This is a simplified interface to PyRun_InteractiveOneFlags() below, leaving flags set to NULL.

Read and execute a single statement from a file associated with an interactive device according to the flags argument. If filename is NULL, "???" is used instead. The user will be prompted using sys.ps1 and sys.ps2. Returns 0 when the input was executed successfully, -1 if there was an exception, or an error code from the errcode.h include file distributed as part of Python if there was a parse error. (Note that errcode.h is not included by Python.h, so must be included specifically if needed.)

This is a simplified interface to PyRun_InteractiveLoopFlags() below, leaving flags set to NULL.

Read and execute statements from a file associated with an interactive device until EOF is reached. If filename is NULL, "???" is used instead. The user will be prompted using sys.ps1 and sys.ps2. Returns 0 at EOF.

This is a simplified interface to PyParser_SimpleParseStringFlagsFilename() below, leaving filename set to NULL and flags set to 0.

This is a simplified interface to PyParser_SimpleParseStringFlagsFilename() below, leaving filename set to NULL.

Parse Python source code from str using the start token start according to the flags argument. The result can be used to create a code object which can be evaluated efficiently. This is useful if a code fragment must be evaluated many times.

This is a simplified interface to PyParser_SimpleParseFileFlags() below, leaving flags set to 0

Similar to PyParser_SimpleParseStringFlagsFilename(), but the Python source code is read from fp instead of an in-memory string.

Return value: New reference.
This is a simplified interface to PyRun_StringFlags() below, leaving flags set to NULL.

Return value: New reference.
Execute Python source code from str in the context specified by the dictionaries globals and locals with the compiler flags specified by flags. The parameter start specifies the start token that should be used to parse the source code.

Returns the result of executing the code as a Python object, or NULL if an exception was raised.

Return value: New reference.
This is a simplified interface to PyRun_FileExFlags() below, leaving closeit set to 0 and flags set to NULL.

Return value: New reference.
This is a simplified interface to PyRun_FileExFlags() below, leaving flags set to NULL.

Return value: New reference.
This is a simplified interface to PyRun_FileExFlags() below, leaving closeit set to 0.

Return value: New reference.
Similar to PyRun_StringFlags(), but the Python source code is read from fp instead of an in-memory string. filename should be the name of the file. If closeit is true, the file is closed before PyRun_FileExFlags() returns.

Return value: New reference.
This is a simplified interface to Py_CompileStringFlags() below, leaving flags set to NULL.

Return value: New reference.
Parse and compile the Python source code in str, returning the resulting code object. The start token is given by start; this can be used to constrain the code which can be compiled and should be Py_eval_input, Py_file_input, or Py_single_input. The filename specified by filename is used to construct the code object and may appear in tracebacks or SyntaxError exception messages. This returns NULL if the code cannot be parsed or compiled.

The start symbol from the Python grammar for isolated expressions; for use with Py_CompileString().

The start symbol from the Python grammar for sequences of statements as read from a file or other source; for use with Py_CompileString(). This is the symbol to use when compiling arbitrarily long Python source code.

The start symbol from the Python grammar for a single statement; for use with Py_CompileString(). This is the symbol used for the interactive interpreter loop.

This is the structure used to hold compiler flags. In cases where code is only being compiled, it is passed as int flags, and in cases where code is being executed, it is passed as PyCompilerFlags *flags. In this case, from __future__ import can modify flags.

Whenever PyCompilerFlags *flags is NULL, cf_flags is treated as equal to 0, and any modification due to from __future__ import is discarded.

struct PyCompilerFlags {
    int cf_flags;
}

This bit can be set in flags to cause division operator / to be interpreted as ``true division'' according to PEP 238.
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