push / pop operation
Synopsis
[
]
The [ operation pushes the current shape onto the top of the shape stack. It must be matched by a succeeding ] operation, which pops the shape on top of the shape stack and deletes the shape.
Related
Examples
Rotation Example
Lot > extrude(15) r(scopeCenter, 0, 22.5, 0) X. r(scopeCenter, 0, 22.5, 0) X. r(scopeCenter, 0, 22.5, 0) X.In this example, the extruded shape is rotated three times and assigned to a new shape (X). The rotations build on each other. 

Lot > extrude(15) [ r(scopeCenter, 0, 22.5, 0) X. ] [ r(scopeCenter, 0, 22.5, 0) X. ] [ r(scopeCenter, 0, 22.5, 0) X. ]Encapsulating the rotations and create shape operations with a push/pop pair makes all shapes X coincide. The rotations are independent of each other. 
House Example
House > extrude(10) comp(f) { top : roofHip(45) Roof.  all = House.} House > [ t(0,10,0) roofHip(45) Roof. ] extrude(10) comp(f) { top : NIL  all = House. }Both rules generate the same result. In the second rule, the roof is generated first using push/pop operations. 
Translation Example
House> Cylinder [ t( 0, 0, ' 1) Cylinder ] [ t( 0, 0, '1) Cylinder ] [ t(' 1, 0, 0) Cylinder ] [ t('1, 0, 0) Cylinder ] Cylinder > primitiveCylinder(16, 1, 2)Cylinder assets are inserted five times. Each scope is translated based on the scope of the initial shape. 
Condition Example
Lot > s(1,1,1) [ case scope.sx == 1 : primitiveCube() Cube. else : primitiveCylinder() Cylinder. ]Conditional and stochastic statements must not have preceding operations. Use push and pop to encapsulate a case switch. 
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