1. A method executable by a processor of a computing system, the method comprising: providing a compiler for a first programming language, the first programming language allowing a data assignment to depend on a result of a previous data assignment; accessing in the computing system source code comprising a first portion written in the first programming language and a second portion written in a second programming language, the second programming language preventing a data assignment that depends on a result of a previous data assignment, the second portion comprising a data transformation from a first data structure accessible in the first portion to a second data structure accessible in the first portion; compiling the source code on the computing system using the compiler to generate executable code to be executed by an engine for the first programming language, the engine for the first programming language comprising an interpretation engine to interpret the second portion during execution of the executable code; designating each node of the first data structure referenced in the second portion as a read-only node for execution; designating each node of the second data structure referenced in the second portion as either a read-only node or a write-only node for execution; designating each sub-node of a read-only node of the second data structure as a read-only node for execution; and designating each sub-node of a write-only node of the second data structure as a write-only node for execution.