if, then, elseif, else, endif

Conditional branching

1) Format 1

if <expression> <statement>

Remarks

Executes a <statement>, if <expression> is true(non-zero).

Example

; If A>1, jump to ':label'.
if A>1 goto label

; If result<>0, assign 0 to A.
if result A=0

2) Format 2

if <expression 1> then
  ...
  (Statements for the case:  <expression 1> is true (non-zero).)
  ...
[elseif <expression 2> then]
  ...
  (Statements for the case:  <expression 1> is false (zero) and <expression 2> is true.)
  ...
[elseif <expression N> then]
  ...
  (Statements for the case:  <expression 1>, <expression 2>,... and <expression N-1> are all false, and <expression N> is true.)
  ...
[else]
  ...
  (Statements for the case:  all the conditions above are false (zero).)
  ...
endif

Remarks

'if' and 'elseif' statements must end with 'then'.
'elseif' and 'else' can be omitted.
'endif' can not be omitted.

Example

if a=1 then
  b = 1
  c = 2
  d = 3
endif

if i<0 then
  i=0
else
  i=i+1
endif

if i=1 then
  c = '1'
elseif i=2 then
  c = '2'
elseif i=3 then
  c = '3'
else
  c = '?'
endif

Reference

Expressions and operators