Lset Command

Purpose

1. Moves a string expression, left justified, to a string.

2. Moves the contents of one type variable to another.

Syntax

Lset a$ = b$

Lset t1 = t2

a$	: svar, b$: sexp
t1, t2	: typevars

Description

Lset a$=b$ will, first of all, replace all characters in a$ with spaces. Next, b$ is moved into a$ left justified. If b$ contains more characters than a$, then only as many characters as there are "places" for in a$ are moved.

Similar to VB Lset also moves the contents of one type variable to another.

Example

Lset with strings.

OpenW # 1

Local a$ = String$(15, "-")

Local b$ = "Hello GFA"

Print a$, Len(a$) // prints --------------- 15

Print b$, Len(b$) // prints HelloGFA 9

Lset a$ = b$

Print a$, Len(a$) // prints Hello GFA 15

Lset with a user defined type.

Type a : - Long a : End Type

Type b : - Single b : End Type

Local a As a, b As b

b.b = 1.0

Print LPeek(V:b.b), Hex(LPeek(V:b.b), 16)

Lset a = b

Print a.a, Hex(a.a, 16)

All bytes of the Type variable b are copied into the Type variable a.

Remarks

Lset for types is similar to a = b, but also works with different Type’s. An alternative would be to copy the contents using a memory copy instruction like MemCpy or Bmove. For instance:

MemCpy(V:a, V:b, Min(Len(a), Len(b)))

There exists no implemented command to copy a String variable and a Type variable together (Lset itself works only with String or only with Type’s, not in mixed case). Nevertheless, it’s very simple to copy a Type variable to a string:

Local t As User_defined_Type

Local a$

a$ = Peek$(V:t, SizeOf(t))

or, when a$ has the correct length:

BMove V:t, V:a$, Len(a$)

To move the string contents back to a type variable use Poke$: