Little script to test alternate glyphs in context. Type a test string with blanks (_). See that test string with blanks replaced by selected glyphs.

test_alts-space_center.py

# menuTitle: Test Alt Glyphs in Space Center

from mojo.UI import getDefault, setDefault, preferencesChanged, AskString, OpenSpaceCenter

'''
Little script to test alternate glyphs in context. Type a test string with blanks (_). See that test string with blanks replaced by selected glyphs.
'''

# attempt to remember the last thing you entered
try:
    placeholder = getDefault("testStringForAlts")
except:
    placeholder = "_"


test_string = AskString("Enter test string. Selected glyphs replace “_”", value=placeholder, title='Test Alternate Glyphs in Context')

if test_string != None:
    f = CurrentFont()

    sc_text = ''
    i = 0
    for g_name in f.selectedGlyphNames:
    	g = f[g_name]
    	
    	# avoid using slashed glyph names if we can
    	replacement = f"/{g_name} "
    	if g.unicode:
    	    replacement = str(chr(g.unicode))
    	    
    	sc_text += test_string.replace("_", replacement)
    	if i != len(f.selectedGlyphNames) - 1:
    	    sc_text += "\\n"
    	i += 1
	
    sc = OpenSpaceCenter(f, True)
    sc.setRaw(sc_text)
    
    # save what you entered for the future
    setDefault("testStringForAlts", test_string, validate=True)
    preferencesChanged()