if...igoto -- conditional branch at initialization time, depending on the truth value of the logical expression ia R ib. The branch is taken only if the result is true.
if...kgoto -- conditional branch during performance time, depending on the truth value of the logical expression ka R kb. The branch is taken only if the result is true.
if...goto -- combination of the above. Condition tested on every pass.
if...then -- synthesizes internal labels allowing the ability to specify "if/else/endif" blocks as some traditional programming languages do. Any block that begins with an "if...then" statement must end with an endif statement. elseif and else statements are optional. Any number of elseif statements are allowed. Only one else statement may occur and it must be the last conditional statement before the endif statement. Nested "if...then" statements are allowed.
![]() | Note |
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Note that if the condition uses a k-rate variable (for instance, "if kval > 0"), the if-test and the goto will be ignored during the i-time pass, even if the k-rate variable has already been assigned an appropriate value by an earlier init statement. |
if ia R ib igoto label
if ka R kb kgoto label
if ia R ib goto label
if xa R xb then
where label is in the same instrument block and is not an expression, and where R is one of the Relational operators (<, =, <=, ==, !=) (and = for convenience, see also under Conditional Values).
Here is an example of the if...igoto combination. It uses the files igoto.orc and igoto.sco.
Example 1. Example of the if...igoto combination.
/* igoto.orc */
/* Written by Kevin Conder */
; Initialize the global variables.
sr = 44100
kr = 4410
ksmps = 10
nchnls = 1
; Instrument #1.
instr 1
; Get the value of the 4th p-field from the score.
iparam = p4
; If iparam is 1 then play the high note.
; If not then play the low note.
if (iparam == 1) igoto highnote
igoto lownote
highnote:
ifreq = 880
goto playit
lownote:
ifreq = 440
goto playit
playit:
; Print the values of iparam and ifreq.
print iparam
print ifreq
a1 oscil 10000, ifreq, 1
out a1
endin
/* igoto.orc */
/* igoto.sco */
/* Written by Kevin Conder */
; Table #1: a simple sine wave.
f 1 0 32768 10 1
; p4: 1 = high note, anything else = low note
; Play Instrument #1 for one second, a low note.
i 1 0 1 0
; Play a Instrument #1 for one second, a high note.
i 1 1 1 1
e
/* igoto.sco */
instr 1: iparam = 0.000 instr 1: ifreq = 440.000 instr 1: iparam = 1.000 instr 1: ifreq = 880.000
Here is an example of the if...kgoto combination. It uses the files kgoto.orc and kgoto.sco.
Example 2. Example of the if...kgoto combination.
/* kgoto.orc */
/* Written by Kevin Conder */
; Initialize the global variables.
sr = 44100
kr = 4410
ksmps = 10
nchnls = 1
; Instrument #1.
instr 1
; Change kval linearly from 0 to 2 over
; the period set by the third p-field.
kval line 0, p3, 2
; If kval is greater than or equal to 1 then play the high note.
; If not then play the low note.
if (kval >= 1) kgoto highnote
kgoto lownote
highnote:
kfreq = 880
goto playit
lownote:
kfreq = 440
goto playit
playit:
; Print the values of kval and kfreq.
printks "kval = %f, kfreq = %f\\n", 1, kval, kfreq
a1 oscil 10000, kfreq, 1
out a1
endin
/* kgoto.orc */
/* kgoto.sco */
/* Written by Kevin Conder */
; Table #1: a simple sine wave.
f 1 0 32768 10 1
; Play Instrument #1 for two seconds.
i 1 0 2
e
/* kgoto.sco */
kval = 0.000000, kfreq = 440.000000 kval = 0.999732, kfreq = 440.000000 kval = 1.999639, kfreq = 880.000000