The programming language IBM Informix 4GL goes through a multi-step transformation to C code, which is then compiled and linked with its own runtime library, the ESQL/C (Embedded SQL in C) runtime libraries, and the system's C libraries.
program.4gl - original source codeprogram.4ec - C code with embedded ESQL/C and extended input operationsprogram.ec - C code with embedded ESQL/Cprogram.c - pure C codeprogram.o - object codeprogram - executable
The .4ec phase is a sort of historical accident; originally, the ESQL/C compiler handled both the extended input operations and the ESQL/C, but when the extended operations were removed from the ESQL/C compiler (when the ESQL/C library and compiler was significantly rewritten), the extended input operations were handled by carving out the code that handled that from the original ESQL/C compiler.
A fair number of people have written code generators which write I4GL source from another language, or which preprocess a closely related source code into I4GL before it is submitted to the I4GL compiler.
