.fp 5 CW

.TH NVAL 3 "12 Feb 2003"

.PP

.SH NAME

.PP

\fBnval\fR \- the \f5ksh\fP name/value library

.PP

.SH SYNOPSIS

.ta .8i 1.6i 2.4i 3.2i 4.0i

.SS "HEADERS/LIBRARIES"

.nf

.ft 5

#include <nval.h>

libshell.a -lshell

.ft R

.fi

.SS "DATA TYPES"

.nf

.ft 5

Namval_t;

Namfun_t;

Namarr_t;

Namdisc_t;

.ft R

.fi

.SS "OPENING/CLOSING"

.nf

.ft 5

Namval_t *nv_open(const char *\fIname\fP, Dt_t *\fIdict\fP, int \fIflags\fP);

Namval_t *nv_create(const char *\fIname\fP, Dt_t *\fIdict\fP, int \fIflags\fP, Namfun_t *\fIfp\fP);

Namval_t *nv_namptr(void *\fIptr\fP, int \fIindx\fP);

void nv_close(Namval_t *\fInp\fP);

void nv_delete(Namval_t *\fInp\fP, Dt_t *\fIdict\fP, int \fInofree\fP);

.ft R

.fi

.SS "GETTING AND SETTING VALUES"

.nf

.ft 5

char *nv_getval(Namval_t *\fInp\fP);

Sfdouble_t nv_getnum(Namval_t *\fInp\fP);

char *nv_name(Namval_t *\fInp\fP);

void nv_putval(Namval_t *\fInp\fP, const char *\fIval\fP, int \fIflags\fP);

void nv_unset(Namval_t *\fInp\fP, int \fIflags\fP);

int nv_clone(Namval_t *\fIsrc\fP, Namval_t *\fIdest\fP, int \fIflags\fP);

.ft R

.fi

.SS "ATTRIBUTES AND SIZE"

.nf

.ft 5

int nv_isnull(Namval_t *\fInp\fP);

int nv_setsize(Namval_t *\fInp\fP, int \fIsize\fP);

int nv_size(Namval_t *\fInp\fP);

unsigned nv_isattr(Namval_t *\fInp\fP, unsigned \fIflags\fP);

Namfun_t *nv_isvtree(Namval_t *\fInp\fP);

unsigned nv_onattr(Namval_t *\fInp\fP, unsigned \fIflags\fP);

unsigned nv_offattr(Namval_t *\fInp\fP, unsigned \fIflags\fP);

void nv_newattr(Namval_t *\fInp\fP, unsigned \fIflags\fP, int \fIsize\fP);

.ft R

.fi

.SS "ARRAY HANDLING"

.nf

.ft 5

unsigned nv_isarray(Namval_t *\fInp\fP);

Namarr_t *nv_setarray(Namval_t *\fInp\fP,void*(*\fIfun\fP)(Namval_t*,const char*,int));

Namarr_t *nv_arrayptr(Namval_t *\fInp\fP);

Namval_t *nv_putsub(Namval_t *\fInp\fP, char *\fIname\fP, long \fImode\fP);

Namval_t *nv_opensub(Namval_t *\fInp\fP);

void nv_setvec(Namval_t *\fInp\fP, int \fIappend\fP, int \fIargc\fP, char *\fIargv\fP[]);

char *nv_getsub(Namval_t *\fInp\fP);

int nv_nextsub(Namval_t *\fInp\fP);

int nv_aindex(Namval_t *\fInp\fP);

.ft R

.fi

.SS "DISCIPLINES"

.nf

.ft 5

Namfun_t *nv_disc(Namval_t *\fInp\fP, Namfun_t *\fIfp\fP, int \fIflags\fP);

Namfun_t *nv_hasdisc(Namval_t *\fInp\fP, const Namdisc_t *\fIdp\fP);

char *nv_getv(Namval_t *\fInp\fP, Namfun_t *\fIfp\fP);

Sfdouble_t nv_getn(Namval_t *\fInp\fP, Namfun_t *\fIfp\fP);

void nv_putv(Namval_t *\fInp\fP, const char *\fIval\fP, int \fIflags\fP, Namfun_t *\fIfp\fP);

char *nv_setdisc(Namval_t *\fInp\fP, const char *\fIa\fP, Namval_t *\fIf\fP, Namfun_t *\fIfp\fP);

char *nv_adddisc(Namval_t *\fInp\fP, const char **\fInames\fP);

const Namdisc_t *nv_discfun(int \fIwhich\fP);

.ft R

.fi

.SS "TYPES"

.nf

.ft 5

Namval_t *nv_type(Namval_t *\fInp\fP);

int *nv_settype(Namval_t *\fInp\fP, Namval_t *\fItp\fP, int \fIflags\fP);

Namval_t *nv_mkinttype(char *\fIname\fP, size_t \fIsz\fP, int \fIus\fP, const char *\fIstr\fP, Namdisc_t *\fIdp\fP);

void nv_addtype(Namval_t *\fInp\fP, const char *\fIstr\fP, Optdisc_t* *\fIop\fP, size_t \fIsz\fP);

.ft R

.fi

.SS "MISCELLANEOUS FUNCTIONS"

.nf

.ft 5

int nv_scan(Dt_t *\fIdict\fP, void(*\fIfn\fP)(Namval_t*,void*), void *\fIdata\fP, int \fImask\fP, int \fIflags\fP);

Dt_t *nv_dict(Namval_t *\fInp\fP);

void nv_setvtree(Namval_t *\fInp\fP);

void nv_setref(Namval_t *\fInp\fP, Dt_t *\fIdp\fP, int \fIflags\fP);

Namval_t *nv_lastdict(void);

.ft R

.fi

.PP

.SH DESCRIPTION

.PP

\fINval\fP is a library of functions for interacting with name-value

pairs as used in \f5ksh\fP.

It is built on top the container dictionary type library facility

in \f5libcdt\fP. (See cdt(3)).

Each name-value pair is represented by a

type named \f5Namval_t\fP.

A \f5Namval_t\fP contains the name, value and

attributes of a variable.

Some attributes can have an associated number that

represents the field width, arithmetic base, or precision.

Additionally, each name-value pair can be associated with

one or more processing disciplines that affect

its behavior.

.PP

The function \f5nv_open()\fP returns a pointer to a name-value

pair corresponding to the given \fIname\fP.

It can also assign a value and give attributes to a name-value pair.

The argument \fIdict\fP defines the dictionary to search.

A \f5NULL\fP value causes the shell global variable dictionary to be searched.

.PP

The \fIflags\fP argument consists of the bitwise-or of zero or more

of the attributes listed later and zero or more of the following:

.IP

\f5NV_VARNAME\fP:

An invalid variable name causes an error.

.IP

\f5NV_IDENTIFIER\fP:

A variable name that is not an identifier causes an error.

.IP

\f5NV_ASSIGN\fP:

The \fIname\fP argument can contain an assignment.

.IP

\f5NV_NOARRAY\fP:

The \fIname\fP argument cannot contain a subscript.

.IP

\f5NV_NOREF\fP:

Do not follow references when finding the name-value pair.

.IP

\f5NV_NOADD\fP:

The name-value pair will not be added if it doesn't exist.

Instead, a \f5NULL\fP pointer will be returned.

.IP

\f5NV_NOSCOPE\fP:

Only the top level scope is used.

.IP

\f5NV_NOFAIL\fP:

Just return \f5NULL\fP when an error occurs.

By default an error message is displayed and the current command

is aborted.

.IP

.PP

If a name-value pair by this name does not already exist, it is

created unless \fIflags\fP contains the \f5NV_NOADD\fP flag.

If \f5NV_VARNAME\fP, \f5NV_IDENTIFIER\fP and \f5NV_ASSIGN\fP are

all not specified, then no validity check is performed on the \fIname\fP

argument and no further processing is performed.

Otherwise, if \f5NV_ASSIGN\fP is specified, then the characters up

to the first \f5=\fP or \f5+=\fP are used to find the name-value pair,

and the characters after the \f5=\fP are used to define

the value that will be assigned to this name-value pair.

If \fIname\fP does not contain an \f5=\fP, than no assignment

will be made.

If the first identifier in \fIname\fP is a reference and is not

preceded by a \fB.\fP,

it will be replaced by the value of the reference

to find the name of a variable.

Unless \fIflags\fP contains the \f5NV_NOREF\fP flag,

if the name-value pair give by \fIname\fP has the \f5NV_REF\fP

attribute, it will be replaced by the variable whose name

is the value of this name-value pair.

If \f5NV_ASSIGN\fP is set in the \fIflags\fP argument,

the \fIname\fP variable can contain an \f5=\fP

and a value that will be assigned to the name-value pair.

Any attributes appearing in the \fIflags\fP argument

will be applied to the name-value pair after any value is assigned.

.PP

It is possible for an application to create additional dictionaries

with the cdt library and associate them with name-value pairs.

The \f5nv_dict()\fP function returns the dictionary associated with

the specified name-value pair, or if no dictionary was specified,

\f5NULL\fP is returned.

The \f5nv_lastdict()\fP function returns a pointer the the

name-value pair that contains

the last dictionary searched on the previous \f5nv_open()\fP.

.PP

Name-value pairs can also be allocated without belonging to

a dictionary. They will typically be looked by a a \fIcreate\fP

discipline associated with a parent node. In this case the

node size will by \f5NV_MINSZ\fP and \fIn\fP nodes can be allocated

vial \f5calloc(5NV_MINSZ,\fIn\fP)\fP(3).

The \f5nv_namptr\fP function can be used on the pointer returned by

\f5calloc\fP along with the element number to return the

corresponding node.

Each of these nodes must be given the \f5NV_MINIMAL\fP attributes.

.PP

The \f5nv_close()\fP indicates that the pointer returned by

\f5nv_open()\fP or \f5nv_opensub()\fP will not be referenced again. If the

name-value pair is unset, and not referenced elsewhere,

the name-value pair may be freed.

.PP

The \f5nv_delete()\fP function will remove the node \fInp\fP from

the dictionary \fIdict\fP. Unless \fInofree\fP is non-zero, the

node \fInp\fP will also be freed.

.PP

The \f5nv_name()\fP function returns the name of the given name-value

pair \fInp\fP.

The \f5nv_setsize()\fP function returns the size of the field for

justified variables, the arithmetic base for integer variables,

and the precision or number of places after the decimal point

for floating point variables. If \fIsize\fP is greater than or

equal to zero, the current size is changed to this value.

The \f5nv_size()\fP function is equivalent to \f5nv_setsize()\fP

with the second argument negative.

.PP

The \f5nv_getval()\fP function returns the value of the given

name-value pair as a string. A \f5NULL\fP return value indicates

that the name-value pair is unset.

The \f5nv_getnum()\fP function returns the value of the given

name-value pair as a double precision number using the \f5Sfio\fP

library (See Sfio(3)) type \f5Sfdouble_t\fP.

For name-value pairs without the \f5NV_INTEGER\fP attribute,

the string value is evaluated as an arithmetic expression to

arrive at a numerical value.

.PP

The \f5nv_putval()\fP function is used to assign a \fIvalue\fP to

the name-value pair \fInp\fP.

The \fIflags\fP argument consists zero or more of the bitwise-or

of \f5NV_LONG\fP, \f5NV_SHORT\fP, \f5NV_DOUBLE\fP, \f5NV_INTEGER\fP,

\f5NV_RDONLY\fP, \f5NV_REF\fP, \f5NV_BINARY\fP, and \f5NV_NOFREE\fP.

The presence of \f5NV_RDONLY\fP allows the assignment to occur

even if the name-value pair has the \f5NV_RDONLY\fP attribute.

The presence of \f5NV_INTEGER\fP indicates that the \fIvalue\fP

argument is actually a pointer to a numerical type.

By default this type is \f5long\fP, but can be modified with

\f5NV_LONG\fP, \f5NV_SHORT\fP, and \f5NV_DOUBLE\fP

to represent \f5long long\fP, \f5short\fP, \f5double\fP, \f5long double\fP,

and \f5float\fP.

The presence of \f5NV_REF\fP indicates that the \fIvalue\fP

argument is actually a pointer to a name-value pair

and \f5np\fP should become a reference to this name-value pair.

If \f5NV_NOFREE\fP is specified, \fIvalue\fP itself becomes

the value of the name-value pair \fInp\fP.

Otherwise, a copy of the value is stored

as the value for \fInp\fP.

.PP

The \f5nv_unset()\fP function clears out the value and attributes

of the given name-value function but does not free the name-value

pair.

If called from the \f5putval\fP discipline function, use the \fIflags\fP

argument as the \fIflags\fP to \f5nv_unset()\fP. Otherwise, use 0.

.PP

The following attributes can be associated with a name-value pair:

.IP

\f5NV_EXPORT\fP:

The export attribute.

.IP

\f5NV_RDONLY\fP:

The readonly attribute.

.IP

\f5NV_LTOU\fP:

Lower case characters are converted to upper case characters.

.IP

\f5NV_UTOL\fP:

Upper case characters are converted to lower case characters.

.IP

\f5NV_RJUST\fP:

Right justify and blank fill.

This attribute has an associated size that defines the

string length of the value.

.IP

\f5NV_LJUST\fP:

Left justify and blank fill.

This attribute has an associated size that defines the

string length of the value.

.IP

\f5NV_ZFILL\fP:

Without \f5NV_LJUST\fP, right justifies and fills with leading zeros.

With \f5NV_LJUST\fP, left justify and strip leading zeros.

Left justify and blank fill.

This attribute has an associated size that defines the

string length of the value.

.IP

\f5NV_TAGGED\fP:

Indicates the tagged attribute.

.IP

\f5NV_INTEGER\fP:

Causes value to be represented by a number.

This attribute has an associated number that defines the

arithmetic base to be used when the value is expanded as a string.

.IP

\f5NV_DOUBLE\fP:

Used in conjunction with \f5NV_INTEGER\fP to cause value

to be stored as a double precision floating point number.

This attribute has an associated number that defines the

number of places after the decimal point to be used when

the value is expanded as a string.

.IP

\f5NV_EXPNOTE\fP:

Used in conjunction with \f5NV_INTEGER\fP and \f5NV_DOUBLE\fP to

cause the value to be represented in scientific notation when

expanded as a string.

This attribute has an associated number that defines the

the precision of the mantissa.

.IP

\f5NV_HEXFLOAT\fP:

Used in conjunction with \f5NV_INTEGER\fP and \f5NV_DOUBLE\fP to

cause the value to be represented in C99 %a format when expanded as

a string.

.IP

\f5NV_BINARY\fP:

The name-value pair contains a buffer of binary data and \f5nv_size()\fP

is the number of bytes for this data. By default the value

will be represented by the base64 encoding of the buffer.

The \f5NV_LJUST\fP flag may also be specified and causes the buffer

size to be fixed and data either truncated or filled with \f50\fP bytes.

.IP

\f5NV_REF\fP:

The name-value pair is a name reference variable.

.IP

\f5NV_MINIMAL\fP:

The name-value pair node is not embedded in a dictionary

and is minimal size, \f5NV_MINSZ\fP.

.IP

\f5NV_NODISC\fP:

All discipline functions are ignored when performing assignments

and lookups.

.PP

The \f5nv_isattr()\fP function can test whether or not any of

the attributes given by \fIflags\fP is set.

The \f5nv_onattr()\fP and \f5nv_offattr()\fP functions turn attributes

on or off respectively. Only attributes that do not affect the

value can be set in this way.

The \f5nv_newattr()\fP function can be used to change the

attributes and size of the given name-value pair which may result

in the value being changed to conform to the new attributes and size.

The \fIsize\fP argument is needed for attributes that require

an additional argument such as justifies variables.

Changing the attribute may require changing the value

to agree with the new attributes.

For an array variable, the values for each of the

subscripts will be changed.

.PP

The \f5nv_isvtree()\fP function returns a pointer to the compound

variable discipline if the node \fInp\fP is a compound variable

or \f5NULL\fP otherwise.

.PP

The \f5nv_isarray()\fP function returns a non-zero value if the specified

name-value pair is an array.

.PP

The \f5nv_scan()\fP function is used to walk through

all name-value pairs in the dictionary given by \fIdict\fP.

If the \f5flags\fP variable contains the \f5NV_NOSCOPE\fP

flag, then only the top scope will be examined.

The remaining flags will be used in conjunction with \fImask\fP

to further restrict the walk.

If \fImask\fP is non-zero, only the nodes for which

\f5nv_isattr(\fP\fInode\fP\f5,\fP\fImask\fP\f5)\fP

is equal to \fIflags\fP will be visited.

If \fIfn\fP is non-zero, then this function will be executed

for each name-value pair in the walk.

The arguments to \fIfn\fP will be a pointer to the name-value pair

and the \fIdata\fP pointer passed to \f5nv_scan()\fP.

The number of elements visited will be returned.

.PP

The \f5nv_clone()\fP function is used make a copy of the contents of

name-value pair \fIsrc\fP to another name-value pair \fIdest\fP.

.PP

Disciplines provide a way to

intercept the lookup and assignment operations,

to manage the creation of sub-variables,

and to extend the operations permitted on a name-value pair.

A discipline consists of a set of one or more functions and related

data that are used to override and extend the operations

on a name-value pair.

A discipline is defined by the types

\f5Namfun_t\fP and \f5Namdisc_t\fP.

The \f5Namdisc_t\fP is not modified by any of these functions and

can therefore be shared by several name-value pairs.

It contains following public fields in the order listed:

.nf

\f5size_t dsize;\fP

\f5void (*putval)(Namval_t*,const char*,int,Namfun_t*);\fP

\f5char *(*getval)(Namval_t*,Namfun_t*);\fP

\f5double (*getnum)(Namval_t*,Namfun_t*);\fP

\f5char *(*setdisc)(Namval_t*,const char*,Namval_t*,Namfun_t*);\fP

\f5Namval_t *(*createf)(Namval_t*,const char*,Namfun_t*);\fP

\f5Namfun_t *(*clonef)(Namval_t*,Namval_t*,int,Namfun_t*);\fP

\f5char *(*namef)(Namval_t*,Namfun_t*);\fP

\f5Namval_t *(*nextf)(Namval_t*,Dt_t*,Namfun_t*);\fP

\f5Namval_t *(*typef)(Namval_t*,Namfun_t*);\fP

.fi

The \f5Namfun_t\fP type contains a member named

\f5disc\fP which points to a \f5Namdisc_t\fP structure.

To create a discipline with additional user data,

define a structure with an instance of \f5Namfun_t\fP

as the first element.

An application must initialize the \f5Namfun_t\fP portion of

the structure to zero and then set the \fIdisc\fP field to point

to the \f5Namdisc_t\fP structure.

The \f5dsize\fP field of the \f5Namdisc_t\fP structure must be

the size of this structure. A value of 0,

indicates that there are no additional fields and is equivalent

to \f5sizeof(Namfun_t)\fP.

If different instances of this structure uses different sizes, then

the \f5size\fP field in the \f5Namfun_t\fP can must be set to

this size and overrides the value in the \f5Namdisc_t\fP structure.

.PP

When a variable is referenced by calling the \f5nv_getval()\fP function,

and the \f5NV_NODISC\fP attribute is not set,

the \f5getval()\fP discipline function is called with a pointer

to the name-value pair, \fInp\fP, and a pointer to the discipline,

\fIfp\fP.

Inside the \f5getval()\fP function, the \f5nv_getv()\fP function

can be called to get the value of the name-value pair that

would have resulted if the discipline were not used.

The \f5getnum()\fP discipline is called whenever a numerical

value is needed for the name-value pair \fInp\fP

and the \f5NV_NODISC\fP attribute is not set,

The \f5nv_getn()\fP function can be called from within

the \f5getnum()\fP discipline to get the value that would

have resulted if there were no \f5getnum()\fP discipline.

.PP

The \f5putval\fP\f5()\fP discipline function is used to

override the assignment of values

to a name-value pair.

It is called whenever a value is assigned with \f5nv_putval()\fP

and the \f5NV_NODISC\fP attribute is not set,

or when a name-value pair is unset with \f5nv_unset()\fP.

When a name-value pair is unset, \f5putval\fP\f5()\fP

is called with \fIvalue\fP set to \f5NULL\fP.

The \f5nv_putv()\fP function is used within the \f5putval()\fP

to perform the assignment or unset that would have occurred

if the discipline had not been installed.

.PP

The \f5createf()\fP discipline function is called from

\f5nv_open()\fP or \f5nv_create()\fP when the name-value pair preceding a

.B \s+2.\s-2

is found.

This function is passed the name-value pointer plus the remaining string and

the current \fIflags\fP argument.

The \f5createf()\fP discipline function

must return the created name-value pair, otherwise the default action

will be taken.

If the name-value pair that is returned is the same as the

one given, then the the behavior will be the same as if

an invalid name had been given to \f5nv_open()\fP.

The \f5nv_create()\fP function may be called within

the \f5createf()\fP discipline function

to perform the action that would have occurred

by an earlier \f5nv_open()\fP function.

.PP

The \f5setdisc()\fP discipline function is used

to extend the set of available shell level discipline functions

associated with a name-value pair by allowing

builtins or functions whose name is of the

form \fIvarname\fP\f5.\fP\fIaction\fP to be defined.

By default, each name-value pair can have a \f5get\fP,

\f5set\fP, and \f5unset\fP discipline associated with it.

Whenever a builtin or function whose name is of the

form \fIvarname\fP\f5.\fP\fIaction\fP is defined or is unset,

and \fIaction\fP is not \f5get\fP,

\f5set\fP, or \f5unset\fP, the \fIsetdisc\fP\f5()\fP function is invoked

with the same argument format as \f5nv_setdisc\fP\f5()\fP.

The argument \fIf\fP points to the name-value pair associated

with the function being defined, or \f5NULL\fP if the function is

being unset.

If the given action \fIa\fP is not known by this discipline,

it should return the value returned by calling

\f5nv_setdisc(\fP\fInp\fP\f5,\fP\fIa\fP\f5,\fP\fIf\fP\f5,\fP\fIfp\fP\f5)\fP

so that it can be searched for in previously stacked disciplines.

Otherwise, the \fIsetdisc\fP\f5()\fP function should save the function

name-value pair pointer, and return a non-\f5NULL\fP value.

The name-value pointer to the function can be used to invoke

the function at an application defined point.

If the action \fIa\fP is \f5NULL\fP, then \fIf\fP points to

an action name instead of a name-value pair pointer.

The \fIsetdisc\fP\f5()\fP must return the

name of the action that follows the action name given by

\fIf\fP. If \fIf\fP is also \f5NULL\fP, the name of the first action

must be returned.

This allows an application to get the list of valid discipline

action names allowed by a given name-value pair.

.PP

The \f5nv_adddisc()\fP function is a higher level function that

adds a \fIsetdisc\fP discipline to the name-value pair that allows

shell level disciplines to be created for each of the name specified

in \f5names\fP.

.PP

The \f5nv_discfun()\fP function can be used to get a pointer to

discipline functions that are provided by the library.

Currently, the only one that is provided is the ones used to

implement \f5nv_adddisc()\fP which can be returned with an

argument of \f5NV_DCADD\fP.

.PP

The \f5clonef()\fP discipline function is called by \f5nv_clone()\fP

when making a copy of the \f5Namfun_t\fP discipline to the new node.

The first argument is the original node, the second argument is

the new node, and the third argument is the flags that were passed

down to \f5nv_clone()\fP.

It must return a new instance of the \f5Namfun_t*\fP \f5fp\fP.

If omitted, then memory whose size is determinated by the \f5size\fP

field of \f5fp\fP, if non-zero, or \f5fp->disc\fP, will be allocated

and copied from \f5fp\fP.

.PP

The \f5namef()\fP discipline function returns the name for this name-value pair.

.PP

The \f5nextf()\fP is used for walking through the list of sub-variables

associated with this name-value pair. If the dictionary argument is

\f5NULL\fP, it must return the first sub-variable. Otherwise,

it must return the next sub-variable, or \f5NULL\fP if there are

no more variables.

.PP

A discipline is installed or removed with the

\f5nv_disc()\fP function.

The following flags can be specified:

.IP

\f5NV_FIRST\fP:

If \fIfp\fP is non-\f5NULL\fP, the discipline is moved to the top

of the stack or pushed onto the top of the stack of disciplines

associated with the given name-value

pair \fInp\fP if not already present.

Otherwise, the top of the discipline stack is returned.

.IP

\f5NV_LAST\fP:

If \fIfp\fP is non-\f5NULL\fP, the discipline is moved to the bottom

of the stack or pushed onto the bottom of the stack of disciplines

associated with the given name-value

pair \fInp\fP if not already present.

Otherwise, the bottom of the discipline stack is returned.

.IP

\f5NV_POP\fP:

If \fIfp\fP is non-\f5NULL\fP and it is on the stack,

it is removed and \fIfp\fP is returned. If \fIfp\fP is non-\f5NULL\fP

and is not on the stack, \f5NULL\fP is returned.

Otherwise, the the top discipline is popped

and returned.

.IP

\f5NV_CLONE\fP:

If \fIfp\fP is non-\f5NULL\fP and it is on the stack,

it is replace by a copy created by \f5malloc\fP(3).

The \f5nofree\fP field is set to \f50\fP.

The new discipline is returned.

Otherwise, \f5NULL\fP is returned.

.IP

\f50\fP:

If \fIfp\fP is non-\f5NULL\fP then it is equivalent to \f5NV_FIRST\fP.

Otherwise, it is equivalent to \f5NV_POP\fP.

.PP

The

\f5nv_hasdisc()\fP function can be used to tell whether a discipline

whose discipline functions are those defined in \fIdp\fP.

A pointer to this discipline is returned.

.PP

The \f5nv_aindex()\fP function returns

the current index for

the indexed array given by the name-value pair pointer \fInp\fP.

The return value is negative if \fInp\fP refers to

an associative array.

.PP

The \f5nv_setarray()\fP function is used to create an associative array

from a name-value pair node.

The function \fIfun\fP defines the semantics of the associative

array.

Using \fIfun\fP equal to \f5nv_associative()\fP implements the default

associative array semantics

that are used with \f5typeset\ -A\fP.

The function \fIfun\fP will be called with third argument as follows:

.IP

\f5NV_AINIT\fP:

This will be called at initialization.

The function you supply must return a pointer to a structure

that contains the type \f5Namarr_t\fP as the first element.

All other calls receive this value as an argument.

.IP

\f5NV_AFREE\fP:

This will be called after all elements of the name-value pair have been

deleted and the array is to be freed.

.IP

\f5NV_ADELETE\fP:

The current element should be deleted.

.IP

\f5NV_ANEXT\fP:

This means that the array subscript should be advanced to the

next subscript. A \f5NULL\fP return indicates that there are

no more subscripts.

.IP

\f5NV_ANAME\fP:

The name of the current subscript must be returned.

.IP

\f5NV_ACURRENT\fP:

Returns a pointer to a name-value pair corresponding to the

current subscript, or \f5NULL\fP if this array type doesn't

create represent each element as a name-value pair.

.IP

\f5NV_ASETSUB\fP:

Set the current subscript to the name-value pair passed in

as the second argument.

.PP

If \fInp\fP refers to an array,

\f5nv_arrayptr()\fP returns a pointer to

the array discipline structure \f5Namarr_t\fP.

Otherwise \f5nv_arrayptr()\fP returns \f5NULL\fP.

.PP

If \fInp\fP refers to an array,

the \f5nv_getsub()\fP returns a pointer to

the name of the current subscript.

Otherwise, \f5nv_getsub()\fP

returns \f5NULL\fP.

.PP

The \f5nv_opensub()\fP function returns

a pointer to the name-value pair corresponding

to the current subscript in an associative array.

Note that the \f5nv_close()\fP function should be called

when the pointer is no longer needed.

.PP

The \f5nv_putsub()\fP function is used to

set the subscript for the next reference to \f5np\fP.

If the \f5name\fP argument is not \f5NULL\fP,

it defines the value of the next subscript.

The \f5mode\fP argument can contain one or more of the following flags:

.IP

\f5ARRAY_ADD\fP:

Add the subscript if not found.

Otherwise, \f5nv_putsub()\fP returns \f5NULL\fP if the

given subscript is not found.

.IP

\f5ARRAY_SCAN\fP:

Begin a walk through the subscripts starting at the subscript

given by \f5name\fP. If \f5name\fP is \f5NULL\fP

the walk is started from the beginning.

.IP

\f5ARRAY_UNDEF\fP:

This causes any current scan to terminate and leaves the

subscript in an undefined state.

.PP

If \f5ARRAY_ADD\fP is not given and the subscript

does not exist, a \f5NULL\fP value is returned.

.PP

The \f5nv_nextsub()\fP function is used to advance to the

next subscript.

It returns 0 if there are no more subscripts or if called

when not in a scan.

.PP

The \f5nv_setref()\fP function makes the name-value pair \f5np\fP

into a reference to the variable whose name is given by

the value of \f5np\fP. The \f5nv_open()\fP open function is

called with this name, the dictionary given by \f5dp\fP,

and the \f5flags\fP argument.

A \f5NULL\fP value causes the shell global variable dictionary to be searched.

.PP

The \f5nv_setvtree()\fP function makes the name-value pair \f5np\fP

into a tree structured variable so that \f5nv_getval()\fP

will return a string containing all the names and values of

children nodes in a format that can be used in

a shell compound assignment.

.PP

The \f5nv_type()\fP function returns a name_value pair pointer

that contains the type definition for the specified name-value pair.

The \fInvname\fP field contains the name for the type.

.PP

The \f5nv_settype()\fP function converts the name-value pair

given by \fInp\fP into the type given by \fItp\fP.

.PP

The \f5nv_addtype()\fP function adds the name of the type given by

\fInp\fP to the list of declaration built-ins. The \fIstr\fP

argument contains the string used by \f5optget\fP(3) to generate

the man page and process the options. The \fIop\fP argument

specifies the callback discipline used by \f5optget\fP(3) and

\fIsz\fP specifies the size of the callback information so

that the discipline \fBoptget\fP(3) can be extended with private

data used by the callback function.

.P

The \f5nv_mkinttype()\fP function creates named integer types

of the specified \fIname\fP. The \fIsize\fP parameter is the size

in bytes of the integer variable and \fIus\fP is non-zero

for unsigned integer types. If \fIdp\fP is specified then integer

variables of this type will all use this discipline.

.SH SEE ALSO

calloc(3)

cdt(3)

shell(3)

optget(3)

.SH AUTHOR

David G. Korn (dgk@research.att.com).