From 267e80d4d45c54fd1e6cda7acfdfec204ce63a47 Mon Sep 17 00:00:00 2001 From: Guido van Rossum Date: Fri, 9 Aug 1996 21:01:07 +0000 Subject: [PATCH] Added doco for abstract interface --- Doc/ext.tex | 2 + Doc/ext/ext.tex | 2 + Doc/extref.tex | 514 ++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 518 insertions(+) create mode 100644 Doc/extref.tex diff --git a/Doc/ext.tex b/Doc/ext.tex index 963f8fff9ee..6603eb061a4 100644 --- a/Doc/ext.tex +++ b/Doc/ext.tex @@ -1364,6 +1364,8 @@ whitespace-separated absolute pathnames of libraries (\samp{.a} files). No \samp{-l} options can be used. +\input{extref} + \input{ext.ind} \end{document} diff --git a/Doc/ext/ext.tex b/Doc/ext/ext.tex index 963f8fff9ee..6603eb061a4 100644 --- a/Doc/ext/ext.tex +++ b/Doc/ext/ext.tex @@ -1364,6 +1364,8 @@ whitespace-separated absolute pathnames of libraries (\samp{.a} files). No \samp{-l} options can be used. +\input{extref} + \input{ext.ind} \end{document} diff --git a/Doc/extref.tex b/Doc/extref.tex new file mode 100644 index 00000000000..755539ac89e --- /dev/null +++ b/Doc/extref.tex @@ -0,0 +1,514 @@ + +\section{Extension Reference} + +From the viewpoint of of C access to Python services, we have: + +\begin{enumerate} + \item "Very high level layer": two or three functions that let you exec or + eval arbitrary Python code given as a string in a module whose name is + given, passing C values in and getting C values out using + mkvalue/getargs style format strings. This does not require the user + to declare any variables of type "PyObject *". This should be enough + to write a simple application that gets Python code from the user, + execs it, and returns the output or errors. + + \item "Abstract objects layer": which is the subject of this proposal. + It has many functions operating on objects, and lest you do many + things from C that you can also write in Python, without going + through the Python parser. + + \item "Concrete objects layer": This is the public type-dependent + interface provided by the standard built-in types, such as floats, + strings, and lists. This interface exists and is currently + documented by the collection of include files provides with the + Python distributions. + + From the point of view of Python accessing services provided by C + modules: + + \item "Python module interface": this interface consist of the basic + routines used to define modules and their members. Most of the + current extensions-writing guide deals with this interface. + + \item "Built-in object interface": this is the interface that a new + built-in type must provide and the mechanisms and rules that a + developer of a new built-in type must use and follow. +\end{enumerate} + + The Python C object interface provides four protocols: object, + numeric, sequence, and mapping. Each protocol consists of a + collection of related operations. If an operation that is not + provided by a particular type is invoked, then a standard exception, + NotImplementedError is raised with a operation name as an argument. + In addition, for convenience this interface defines a set of + constructors for building objects of built-in types. This is needed + so new objects can be returned from C functions that otherwise treat + objects generically. + +\subsubsection{Object Protocol} + \code{int *PyObject_Print(PyObject *o, FILE *fp, int flags)}\\ + Print an object \code{o}, on file \code{fp}. Returns -1 on error + The flags argument is used to enable certain printing + options. The only option currently supported is \code{Py_Print_RAW}. + + \code{int PyObject_HasAttrString(PyObject *o, char *attr_name)}\\ + Returns 1 if o has the attribute attr_name, and 0 otherwise. + This is equivalent to the Python expression: + \code{hasattr(o,attr_name)}. + This function always succeeds. + + \code{PyObject* PyObject_AttrString(PyObject *o, char *attr_name)}\\ + Retrieve an attributed named attr_name form object o. + Returns the attribute value on success, or NULL on failure. + This is the equivalent of the Python expression: \code{o.attr_name}. + + + \code{int PyObject_HasAttr(PyObject *o, PyObject *attr_name)}\\ + Returns 1 if o has the attribute attr_name, and 0 otherwise. + This is equivalent to the Python expression: + \code{hasattr(o,attr_name)}. + This function always succeeds. + + + \code{PyObject* PyObject_GetAttr(PyObject *o, PyObject *attr_name)}\\ + Retrieve an attributed named attr_name form object o. + Returns the attribute value on success, or NULL on failure. + This is the equivalent of the Python expression: o.attr_name. + + + \code{int PyObject_SetAttrString(PyObject *o, char *attr_name, PyObject *v)}\\ + Set the value of the attribute named \code{attr_name}, for object \code{o}, + to the value \code{v}. Returns -1 on failure. This is + the equivalent of the Python statement: \code{o.attr_name=v}. + + + \code{int PyObject_SetAttr(PyObject *o, PyObject *attr_name, PyObject *v)}\\ + Set the value of the attribute named \code{attr_name}, for object \code{o}, + to the value \code{v}. Returns -1 on failure. This is + the equivalent of the Python statement: \code{o.attr_name=v}. + + + \code{int PyObject_DelAttrString(PyObject *o, char *attr_name)}\\ + Delete attribute named \code{attr_name}, for object \code{o}. Returns -1 on + failure. This is the equivalent of the Python + statement: \code{del o.attr_name}. + + + \code{int PyObject_DelAttr(PyObject *o, PyObject *attr_name)}\\ + Delete attribute named \code{attr_name}, for object \code{o}. Returns -1 on + failure. This is the equivalent of the Python + statement: \code{del o.attr_name}. + + + \code{int PyObject_Cmp(PyObject *o1, PyObject *o2, int *result)}\\ + Compare the values of \code{o1} and \code{o2} using a routine provided by + \code{o1}, if one exists, otherwise with a routine provided by \code{o2}. + The result of the comparison is returned in \code{result}. Returns + -1 on failure. This is the equivalent of the Python + statement: \code{result=cmp(o1,o2)}. + + + \code{int PyObject_Compare(PyObject *o1, PyObject *o2)}\\ + Compare the values of \code{o1} and \code{o2} using a routine provided by + \code{o1}, if one exists, otherwise with a routine provided by \code{o2}. + Returns the result of the comparison on success. On error, + the value returned is undefined. This is equivalent to the + Python expression: \code{cmp(o1,o2)}. + + + \code{PyObject *PyObject_Repr(PyObject *o)}\\ + Compute the string representation of object, \code{o}. Returns the + string representation on success, NULL on failure. This is + the equivalent of the Python expression: \code{repr(o)}. + Called by the \code{repr()} built-in function and by reverse quotes. + + + \code{PyObject *PyObject_Str(PyObject *o)}\\ + Compute the string representation of object, \code{o}. Returns the + string representation on success, NULL on failure. This is + the equivalent of the Python expression: \code{str(o)}. + Called by the \code{str()} built-in function and by the \code{print} + statement. + + + \code{int *PyCallable_Check(PyObject *o))}\\ + Determine if the object \code{o}, is callable. Return 1 if the + object is callable and 0 otherwise. + This function always succeeds. + + + \code{PyObject *PyObject_CallObject(PyObject *callable_object, PyObject *args)}\\ + Call a callable Python object \code{callable_object}, with + arguments given by the tuple \code{args}. If no arguments are + needed, then args may be NULL. Returns the result of the + call on success, or NULL on failure. This is the equivalent + of the Python expression: \code{apply(o,args)}. + + \code{PyObject *PyObject_CallFunction(PyObject *callable_object, char *format, ...)}\\ + Call a callable Python object \code{callable_object}, with a + variable number of C arguments. The C arguments are described + using a mkvalue-style format string. The format may be NULL, + indicating that no arguments are provided. Returns the + result of the call on success, or NULL on failure. This is + the equivalent of the Python expression: \code{apply(o,args)}. + + + \code{PyObject *PyObject_CallMethod(PyObject *o, char *m, char *format, ...)}\\ + Call the method named \code{m} of object \code{o} with a variable number of + C arguments. The C arguments are described by a mkvalue + format string. The format may be NULL, indicating that no + arguments are provided. Returns the result of the call on + success, or NULL on failure. This is the equivalent of the + Python expression: \code{o.method(args)}. + Note that Special method names, such as "\code{__add__}", + "\code{__getitem__}", and so on are not supported. The specific + abstract-object routines for these must be used. + + + \code{int PyObject_Hash(PyObject *o)}\\ + Compute and return the hash value of an object \code{o}. On + failure, return -1. This is the equivalent of the Python + expression: \code{hash(o)}. + + + \code{int *PyObject_IsTrue(PyObject *o)}\\ + Returns 1 if the object \code{o} is considered to be true, and + 0 otherwise. This is equivalent to the Python expression: + \code{not not o}. + This function always succeeds. + + + \code{PyObject *PyObject_Type(PyObject *o)}\\ + On success, returns a type object corresponding to the object + type of object \code{o}. On failure, returns NULL. This is + equivalent to the Python expression: \code{type(o)}. + + \code{int PyObject_Length(PyObject *o)}\\ + Return the length of object \code{o}. If the object \code{o} provides + both sequence and mapping protocols, the sequence length is + returned. On error, -1 is returned. This is the equivalent + to the Python expression: \code{len(o)}. + + + \code{PyObject *PyObject_GetItem(PyObject *o, PyObject *key)}\\ + Return element of \code{o} corresponding to the object \code{key} or NULL + on failure. This is the equivalent of the Python expression: + \code{o[key]}. + + + \code{int PyObject_SetItem(PyObject *o, PyObject *key, PyObject *v)}\\ + Map the object \code{key} to the value \code{v}. + Returns -1 on failure. This is the equivalent + of the Python statement: \code{o[key]=v}. + + +\subsubsection{Number Protocol} + + \code{int PyNumber_Check(PyObject *o)}\\ + Returns 1 if the object \code{o} provides numeric protocols, and + false otherwise. + This function always succeeds. + + + \code{PyObject *PyNumber_Add(PyObject *o1, PyObject *o2)}\\ + Returns the result of adding \code{o1} and \code{o2}, or null on failure. + This is the equivalent of the Python expression: \code{o1+o2}. + + + \code{PyObject *PyNumber_Subtract(PyObject *o1, PyObject *o2)}\\ + Returns the result of subtracting \code{o2} from \code{o1}, or null on + failure. This is the equivalent of the Python expression: + \code{o1-o2}. + + + \code{PyObject *PyNumber_Multiply(PyObject *o1, PyObject *o2)}\\ + Returns the result of multiplying \code{o1} and \code{o2}, or null on + failure. This is the equivalent of the Python expression: + \code{o1*o2}. + + + \code{PyObject *PyNumber_Divide(PyObject *o1, PyObject *o2)}\\ + Returns the result of dividing \code{o1} by \code{o2}, or null on failure. + This is the equivalent of the Python expression: \code{o1/o2}. + + + \code{PyObject *PyNumber_Remainder(PyObject *o1, PyObject *o2)}\\ + Returns the remainder of dividing \code{o1} by \code{o2}, or null on + failure. This is the equivalent of the Python expression: + \code{o1\%o2}. + + + \code{PyObject *PyNumber_Divmod(PyObject *o1, PyObject *o2)}\\ + See the built-in function divmod. Returns NULL on failure. + This is the equivalent of the Python expression: + \code{divmod(o1,o2)}. + + + \code{PyObject *PyNumber_Power(PyObject *o1, PyObject *o2, PyObject *o3)}\\ + See the built-in function pow. Returns NULL on failure. + This is the equivalent of the Python expression: + \code{pow(o1,o2,o3)}, where \code{o3} is optional. + + + \code{PyObject *PyNumber_Negative(PyObject *o)}\\ + Returns the negation of \code{o} on success, or null on failure. + This is the equivalent of the Python expression: \code{-o}. + + + \code{PyObject *PyNumber_Positive(PyObject *o)}\\ + Returns \code{o} on success, or NULL on failure. + This is the equivalent of the Python expression: \code{+o}. + + + \code{PyObject *PyNumber_Absolute(PyObject *o)}\\ + Returns the absolute value of \code{o}, or null on failure. This is + the equivalent of the Python expression: \code{abs(o)}. + + + \code{PyObject *PyNumber_Invert(PyObject *o)}\\ + Returns the bitwise negation of \code{o} on success, or NULL on + failure. This is the equivalent of the Python expression: + \code{~o}. + + + \code{PyObject *PyNumber_Lshift(PyObject *o1, PyObject *o2)}\\ + Returns the result of left shifting \code{o1} by \code{o2} on success, or + NULL on failure. This is the equivalent of the Python + expression: \code{o1 << o2}. + + + \code{PyObject *PyNumber_Rshift(PyObject *o1, PyObject *o2)}\\ + Returns the result of right shifting \code{o1} by \code{o2} on success, or + NULL on failure. This is the equivalent of the Python + expression: \code{o1 >> o2}. + + + \code{PyObject *PyNumber_And(PyObject *o1, PyObject *o2)}\\ + Returns the result of "anding" \code{o2} and \code{o2} on success and NULL + on failure. This is the equivalent of the Python + expression: \code{o1 and o2}. + + + \code{PyObject *PyNumber_Xor(PyObject *o1, PyObject *o2)}\\ + Returns the bitwise exclusive or of \code{o1} by \code{o2} on success, or + NULL on failure. This is the equivalent of the Python + expression: \code{o1\^{ }o2}. + + \code{PyObject *PyNumber_Or(PyObject *o1, PyObject *o2)}\\ + Returns the result or \code{o1} and \code{o2} on success, or NULL on + failure. This is the equivalent of the Python expression: + \code{o1 or o2}. + + + \code{PyObject *PyNumber_Coerce(PyObject *o1, PyObject *o2)}\\ + On success, returns a tuple containing \code{o1} and \code{o2} converted to + a common numeric type, or None if no conversion is possible. + Returns -1 on failure. This is equivalent to the Python + expression: \code{coerce(o1,o2)}. + + + \code{PyObject *PyNumber_Int(PyObject *o)}\\ + Returns the \code{o} converted to an integer object on success, or + NULL on failure. This is the equivalent of the Python + expression: \code{int(o)}. + + + \code{PyObject *PyNumber_Long(PyObject *o)}\\ + Returns the \code{o} converted to a long integer object on success, + or NULL on failure. This is the equivalent of the Python + expression: \code{long(o)}. + + + \code{PyObject *PyNumber_Float(PyObject *o)}\\ + Returns the \code{o} converted to a float object on success, or NULL + on failure. This is the equivalent of the Python expression: + \code{float(o)}. + + +\subsubsection{Sequence protocol} + + \code{int PySequence_Check(PyObject *o)}\\ + Return 1 if the object provides sequence protocol, and 0 + otherwise. + This function always succeeds. + + + \code{PyObject *PySequence_Concat(PyObject *o1, PyObject *o2)}\\ + Return the concatination of \code{o1} and \code{o2} on success, and NULL on + failure. This is the equivalent of the Python + expression: \code{o1+o2}. + + + \code{PyObject *PySequence_Repeat(PyObject *o, int count)}\\ + Return the result of repeating sequence object \code{o} count times, + or NULL on failure. This is the equivalent of the Python + expression: \code{o*count}. + + + \code{PyObject *PySequence_GetItem(PyObject *o, int i)}\\ + Return the ith element of \code{o}, or NULL on failure. This is the + equivalent of the Python expression: \code{o[i]}. + + + \code{PyObject *PySequence_GetSlice(PyObject *o, int i1, int i2)}\\ + Return the slice of sequence object \code{o} between \code{i1} and \code{i2}, or + NULL on failure. This is the equivalent of the Python + expression, \code{o[i1:i2]}. + + + \code{int PySequence_SetItem(PyObject *o, int i, PyObject *v)}\\ + Assign object \code{v} to the \code{i}th element of \code{o}. +Returns -1 on failure. This is the equivalent of the Python + statement, \code{o[i]=v}. + + \code{int PySequence_SetSlice(PyObject *o, int i1, int i2, PyObject *v)}\\ + Assign the sequence object \code{v} to the slice in sequence + object \code{o} from \code{i1} to \code{i2}. This is the equivalent of the Python + statement, \code{o[i1:i2]=v}. + + \code{PyObject *PySequence_Tuple(PyObject *o)}\\ + Returns the \code{o} as a tuple on success, and NULL on failure. + This is equivalent to the Python expression: \code{tuple(o)}. + + \code{int PySequence_Count(PyObject *o, PyObject *value)}\\ + Return the number of occurrences of \code{value} on \code{o}, that is, + return the number of keys for which \code{o[key]==value}. On + failure, return -1. This is equivalent to the Python + expression: \code{o.count(value)}. + + \code{int PySequence_In(PyObject *o, PyObject *value)}\\ + Determine if \code{o} contains \code{value}. If an item in \code{o} is equal to + \code{value}, return 1, otherwise return 0. On error, return -1. This + is equivalent to the Python expression: \code{value in o}. + + \code{int PySequence_Index(PyObject *o, PyObject *value)}\\ + Return the first index for which \code{o[i]=value}. On error, + return -1. This is equivalent to the Python + expression: \code{o.index(value)}. + +\subsubsection{Mapping protocol} + + \code{int PyMapping_Check(PyObject *o)}\\ + Return 1 if the object provides mapping protocol, and 0 + otherwise. + This function always succeeds. + + + \code{int PyMapping_Length(PyObject *o)}\\ + Returns the number of keys in object \code{o} on success, and -1 on + failure. For objects that do not provide sequence protocol, + this is equivalent to the Python expression: \code{len(o)}. + + + \code{int PyMapping_DelItemString(PyObject *o, char *key)}\\ + Remove the mapping for object \code{key} from the object \code{o}. + Return -1 on failure. This is equivalent to + the Python statement: \code{del o[key]}. + + + \code{int PyMapping_DelItem(PyObject *o, PyObject *key)}\\ + Remove the mapping for object \code{key} from the object \code{o}. + Return -1 on failure. This is equivalent to + the Python statement: \code{del o[key]}. + + + \code{int PyMapping_HasKeyString(PyObject *o, char *key)}\\ + On success, return 1 if the mapping object has the key \code{key} + and 0 otherwise. This is equivalent to the Python expression: + \code{o.has_key(key)}. + This function always succeeds. + + + \code{int PyMapping_HasKey(PyObject *o, PyObject *key)}\\ + Return 1 if the mapping object has the key \code{key} + and 0 otherwise. This is equivalent to the Python expression: + \code{o.has_key(key)}. + This function always succeeds. + + + \code{PyObject *PyMapping_Keys(PyObject *o)}\\ + On success, return a list of the keys in object \code{o}. On + failure, return NULL. This is equivalent to the Python + expression: \code{o.keys()}. + + + \code{PyObject *PyMapping_Values(PyObject *o)}\\ + On success, return a list of the values in object \code{o}. On + failure, return NULL. This is equivalent to the Python + expression: \code{o.values()}. + + + \code{PyObject *PyMapping_Items(PyObject *o)}\\ + On success, return a list of the items in object \code{o}, where + each item is a tuple containing a key-value pair. On + failure, return NULL. This is equivalent to the Python + expression: \code{o.items()}. + + \code{int PyMapping_Clear(PyObject *o)}\\ + Make object \code{o} empty. Returns 1 on success and 0 on failure. + This is equivalent to the Python statement: + \code{for key in o.keys(): del o[key]} + + + \code{PyObject *PyMapping_GetItemString(PyObject *o, char *key)}\\ + Return element of \code{o} corresponding to the object \code{key} or NULL + on failure. This is the equivalent of the Python expression: + \code{o[key]}. + + \code{PyObject *PyMapping_SetItemString(PyObject *o, char *key, PyObject *v)}\\ + Map the object \code{key} to the value \code{v} in object \code{o}. Returns + -1 on failure. This is the equivalent of the Python + statement: \code{o[key]=v}. + + +\subsubsection{Constructors} + + \code{PyObject *PyFile_FromString(char *file_name, char *mode)}\\ + On success, returns a new file object that is opened on the + file given by \code{file_name}, with a file mode given by \code{mode}, + where \code{mode} has the same semantics as the standard C routine, + fopen. On failure, return -1. + + \code{PyObject *PyFile_FromFile(FILE *fp, char *file_name, char *mode, int close_on_del)}\\ + Return a new file object for an already opened standard C + file pointer, \code{fp}. A file name, \code{file_name}, and open mode, + \code{mode}, must be provided as well as a flag, \code{close_on_del}, that + indicates whether the file is to be closed when the file + object is destroyed. On failure, return -1. + + \code{PyObject *PyFloat_FromDouble(double v)}\\ + Returns a new float object with the value \code{v} on success, and + NULL on failure. + + \code{PyObject *PyInt_FromLong(long v)}\\ + Returns a new int object with the value \code{v} on success, and + NULL on failure. + + \code{PyObject *PyList_New(int l)}\\ + Returns a new list of length \code{l} on success, and NULL on + failure. + + \code{PyObject *PyLong_FromLong(long v)}\\ + Returns a new long object with the value \code{v} on success, and + NULL on failure. + + \code{PyObject *PyLong_FromDouble(double v)}\\ + Returns a new long object with the value \code{v} on success, and + NULL on failure. + + \code{PyObject *PyDict_New()}\\ + Returns a new empty dictionary on success, and NULL on + failure. + + \code{PyObject *PyString_FromString(char *v)}\\ + Returns a new string object with the value \code{v} on success, and + NULL on failure. + + \code{PyObject *PyString_FromStringAndSize(char *v, int l)}\\ + Returns a new string object with the value \code{v} and length \code{l} + on success, and NULL on failure. + + \code{PyObject *PyTuple_New(int l)}\\ + Returns a new tuple of length \code{l} on success, and NULL on + failure. +