[symfont] Write generator code as main function in printPen() output

Lib/fontTools/pens/momentsPen.py

@@ -270,3 +270,14 @@ class MomentsPen(BasePen):
 		self.momentXX += -r11*r73*(-r61 + y2)/9240 + r21*(r28 - r37*y1 + r44 + r78 + r79)/9240 + r22*(21*r26 - 630*r40 + 42*r41 - 126*r42 + r57*x3 + r82 + 210*r83 + 42*r84 - 14*r85)/9240 - r5*(r11*r62 + r14*r23 + 14*r15 - r76*y3 + 54*r86 - 84*r87 - r89 - r91)/9240 - r6*(27*r71 + 42*r72 + 70*r75 + r77)/9240 + 3*r71*y3/220 - 3*r72*y2/44 - r72*y3/4 + 3*r74*(r57 + r67)/3080 - r75*(378*y2 - 630*y3)/9240 + x0**3*(r57 + r62 + 165*y0 + y3)/660 + x0*(-18*r100 - r101*y0 - r101*y1 + r102*y2 - r103*y0 + r104*r20 + 63*r105 - 27*r106 - 9*r107 + r13 - r34*y0 - r76*y0 + 42*r87 + r92*y3 + r94*y3 + r95 - r97*y0 + 162*r98 - r99*y0)/9240 - y0*(135*r11*x1 + r14*r54 + r20*r93 + r33*x3 + 45*r71 + 14*r72 + 126*r74 + 42*r75 + r77 + r92*x3)/9240
 		self.momentXY += -r108*r14/18480 + r12*(r109 + 378*y3)/18480 - r14*r49/8 - 3*r14*r58/44 - r17*(252*r46 - 1260*r49)/18480 + r21*(18*r110 + r3*y1 + 15*r46 + 7*r49 + 18*r58)/18480 + r22*(252*r110 + 28*r112 + r113 + r114 + 2310*r53 + 30*r58 + 1260*r64 + 252*r65 + 42*r68 + r70)/18480 - r52*(r102 + 15*r11 + 7*r14)/18480 - r53*(r101 + r103 + r34 + r76 + r97 + r99)/18480 + r7*(-r115*r51 + r116 + 18*r117 - 18*r118 + 42*r119 - 15*r120 + 28*r45 + r81*y3)/18480 - r9*(63*r111 + 42*r15 + 28*r87 + r89 + r91)/18480 + x0*(r1*y0 + r104*r80 + r112*r54 + 21*r119 - 9*r120 - r122*r53 + r123 + 54*r124 + 60*r125 + 54*r126 + r127*r35 + r128*y3 - r129*x1 + 81*r130 + 15*r131 - r132*x2 - r2*r85 - r23*r85 + r30*y3 + 84*r40*y2 - 84*r42*y1 + r60*x3)/9240 - y0*(54*r100 - 9*r105 + 81*r106 + 15*r107 + 54*r111 + r121*r7 + 21*r15 + r24*y3 + 60*r86 + 21*r87 + r95 + 189*r96*y1 + 54*r98)/9240
 		self.momentYY += -r108*r121/9240 - r133*r73/9240 - r134*x3/12 - r135*r55/9240 - 3*r136*(r25 + r37)/3080 - r137*(r25 + r31 + x3)/660 + r26*(r135 + 126*r46 + 378*y2*y3)/9240 + r5*(r110*r127 + 27*r133 + 42*r134 + r138 + 70*r139 + r46*r62 + 27*r51*y2 + 15*r51*y3)/9240 - r52*(r56 + r63 + r78 + r79)/9240 - r53*(r128 + r25*y3 + 42*r43 + r82 + 42*r83 + 210*r84)/9240 - r6*(r114*x3 + r116 - 14*r119 + 84*r45)/9240 + x0*(r104*r51 + r109*r64 + 90*r110*y3 + r113*y0 + r114*y0 + r129*y1 + r132*y2 + 45*r133 + 14*r134 + 126*r136 + 770*r137 + r138 + 42*r139 + 135*r46*y1 + 14*r53*y3 + r64*r90 + r66*y3 + r69*y3 + r70*y0)/9240 - y0*(90*r118 + 63*r120 + r123 - 18*r124 - 30*r125 + 162*r126 - 27*r130 - 9*r131 + r36*y3 + 30*r43*y3 + 42*r45 + r48 + r51*r93)/9240
+
+if __name__ == '__main__':
+	from symfont import x, y, printPen
+	printPen('MomentsPen', [
+		 ('area', 1),
+		 ('momentX', x),
+		 ('momentY', y),
+		 ('momentXX', x**2),
+		 ('momentXY', x*y),
+		 ('momentYY', y**2),
+		])

Snippets/symfont.py

@@ -46,17 +46,17 @@ def green(f, curveXY, optimize=True):
 		f = sp.gcd_terms(f.collect(sum(P,())))
 	return f
 
-def printPen(name, funcs, file=sys.stdout):
+def printPen(penName, funcs, file=sys.stdout):
 	print(
 '''from __future__ import print_function, division, absolute_import
 from fontTools.misc.py23 import *
 from fontTools.pens.basePen import BasePen
 
-class {name}(BasePen):
+class %s(BasePen):
 
 	def __init__(self, glyphset=None):
 		BasePen.__init__(self, glyphset)
-'''.format(name=name), file=file)
+'''%penName, file=file)
 	for name,f in funcs:
 		print('		self.%s = 0' % name, file=file)
 	print('''
@@ -101,13 +101,13 @@ class {name}(BasePen):
 		for name,value in zip([f[0] for f in funcs], exprs):
 			print('		self.%s += %s' % (name, value), file=file)
 
-#printPen('MomentsPen',
+	print('''
-#	 [('area', 1),
+if __name__ == '__main__':
-#	  ('momentX', x),
+	from symfont import x, y, printPen
-#	  ('momentY', y),
+	printPen('%s', ['''%penName, file=file)
-#	  ('momentXX', x*x),
+	for name,f in funcs:
-#	  ('momentXY', x*y),
+		print("		 ('%s', %s)," % (name, str(f)), file=file)
-#	  ('momentYY', y*y)])
+	print('		])', file=file)
 
 
 class BezierFuncs(dict):