[Scons-users] Conditional process

[Sven Lars Tobias Stål]

Dear all, 

I’m using SCons to build work flows of Madagascar programs (http://www.ahay.org). I’m new to SCons, so sorry for asking basic questions. I’m grateful for any advice.

I’d like to build files differently based on a variable.

I could easily make a Python script, using os or subprocess to achieve the wanted result, but I’d like to use SCons and implement this process in a larger flow. The loop goes through all file names, check a variable from a list, SN, if it’s 2 it adds the following file and skips i+1. If the variable is 4, it adds the there following files and jump to the file after. 

i = 0
while i < len(fL):
	shutil.copy2('t'+ fL[i]+'.rsf', iN + fL[i]+'.rsf') #Select trace header files
	shutil.copy2('t'+ fL[i]+'.rsf@', iN + fL[i]+'.rsf@')
	sL.append(iN + fL[i] + '.rsf')
	if SN[i] == 2:
		os.popen('sfadd < '+ fL[i] + '.rsf ' + fL[i+1] + \
		'.rsf scale=1,1 > ' + iN + fL[i] + '.rsf').read()
		i += 2 #Jump to next file
	elif SN[i] == 4:
		os.popen('sfadd < '+ fL[i] + '.rsf ' + fL[i+1] + '.rsf ' + fL[i+2] + \
		'.rsf ' + fL[i+3] + '.rsf scale=1,1,1,1 > ' + iN + fL[i] + '.rsf').read() 
		i += 4 #Jump to next file
	else:
		print('Unspecified stack %s' % fL[i]) #Or error

Alternatively, how can I call a python script from SCons so that the input is defined (all files in fL list) but the output depends on the conditional result from the script. 

Regards
Tobbe