PROPERTY_FROM_STRING Function

IN THIS PAGE

Examples
Specifying a Format String
Examples
Copying a Complex Pointer Variable
Copying Data Between Tables with Different Structures

Syntax

V PROPERTY_FROM_STRING(P destination,C source[,C format])

Arguments

destinationPointer: The dot variable to populate.
sourceCharacter: A text string that was originally created using the PROPERTY_TO_STRING() function
formatCharacter: Specifications for formatting the data. Refer to the <ARRAY>.INITIALIZE_PROPERTIES() method.

Description

Recover previously dumped contents back into a pointer, format allows for optional user spec.

Discussion

The PROPERTY_FROM_STRING() function initializes the values in a "dot" variable referenced by Dot_Variable. Property_String is a text string that was originally created using the PROPERTY_TO_STRING()function, and it contains the value of each sub-element of the dot variable. (If the optional Format_String is specified, then Property_String has a different format. See below.)

Examples

Before you initialize variables using PROPERTY_FROM_STRING() , at least one of the dot variables sub-elements must be initialized. For example, assume that you want to initialize a dot variable called "p2". Before the PROPERTY_FROM_STRING() function is used you must execute this Xbasic:

'Declare the dot variable
dim P2 as P
'Initialize a dot variable sub-element.
P2.dummy = ""

Having done this, you can now call the PROPERTY_FROM_STRING() function. For example (Assume that str was previously created using the PROPERTY_TO_STRING() function):

dim p as P
p.dummy = ""
property_from_string(p, str)

Specifying a Format String

If the optional Format_String parameter is specified, then string must be in the format specified in the Format_String. The syntax of the Format_String is the same as is used in the <ARRAY>.INITIALIZE_PROPERTIES()method.

data = "Fred|Smith|46"
format = "first_name:c|last_name:c|age:N"
dim p as P
p.dummy = ""
property_from_string(p, data, format)
? p 
= age = 46.000000
dummy = ""
first_name = "Fred"
last_name = "Smith"

Examples

This example convert the contents of a record to a string, then writes them out in a duplicate record.

dim t as P
dim t2 as P
dim str as C
t = table.open("customer")
t.fetch_goto(targetRecord)
str = property_to_string(t)
t2 = table.open("customer")
t2.enter_begin()
property_from_string(t2,str)
t2.enter_end(.t.)
t.close()
t2.close()

The following is an Interactive Window session:

dim p as P
p.first_name = "Fred"
p.last_name = "Smith"
str = property_to_string(p)
? str
= <first_name="Fred">
<last_name="Smith">

delete p
? p
ERROR: p not found.

dim p as P
'Initialize any variable as a sub-element of p
p.first_name = ""
property_from_string(p, str)
? p
= first_name = "Fred"
last_name = "Smith"

Copying a Complex Pointer Variable

Follow this procedure if you need to copy a complex pointer variable.

' create the initial pointer variable with any set of elements
dim x as P
dim x.name as C
dim x.phone as C
dim x.data[2,2,2] as C
x.data[1,1,1] = "A"
x.data[1,1,2] = "B"
x.data[1,2,1] = "C"
x.data[1,2,2] = "D"
x.data[2,1,1] = "E"
x.data[2,1,2] = "F"
x.data[2,2,1] = "G"
x.data[2,2,2] = "H"

' create the duplicate pointer variable
' explicitly dimension arrays
dim y as P
dim y.data[2,2,2] as C
property_from_string(y, property_to_string(x))

? y
= name = ""
phone = ""

? y.data
= [1,1,1] = "A"
[1,1,2] = "B"
[1,2,1] = "C"
[1,2,2] = "D"
[2,1,1] = "E"
[2,1,2] = "F"
[2,2,1] = "G"
[2,2,2] = "H"

Copying Data Between Tables with Different Structures

Follow this procedure to copy data between tables with different structures.

dim t1 as P
dim t2 as P
t1 = table.open("sourcetable")
t2 = table.open("targettable")
t2.enter_begin()
property_from_string(t2, property_to_string(t1))
t2.enter_end(.t.)
t1.close()
t2.close()