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Met English Language (MEL) was an early computer language used by the Metropolitan Life Insurance Company (MetLife). It enabled MetLife to establish itself as a strong technology company in the early days of commercial computing. It has now been retired and is no longer in use.
Met English was a Fortran-like language. Two of its most peculiar characteristics were bytes and fields of variable "bitness" or length in bits, and the use of self-modifying code (conditional branches were implemented by modifying the target address of branch instructions in memory). The language was very rich in mathematical functions, especially those useful to the insurance industry. It was verbose with syntax like "ADD (A FIELDA) TO (B FIELDB) PUTTING RESULT INTO (ANSWER)".
Met English was used to write some of the most complex business systems of the 1960s. It remained the primary language used by MetLife in the 1970s, but was gradually phased out after the company standardized on IBM hardware and software in the mid-1980s. Met English systems continued to run in the company (with a new IBM compiler that generated IBM assembler language) well into the 1990s. MEL was (almost) entirely retired as part of the preparation for Y2K.
The UNIVAC Compiler
The UNIVAC English Language compiler was the first one produced at MetLife, in 1959. (Other sources indicate 1957.) Its chief value was in the experience gained in the use of the language and in implementing the compiler program. This initial effort made the later H-800 compilers more efficient by allowing improvement attributable to hindsight. The UNIVAC Compiler was used as late as 1964.
The Compromise Compiler
The Compromise English Language Compiler compiled on UNIVAC II but produced H-800 coding. This approach allowed MetLife to have a compiling system in existence for the H-800 almost as soon as the machines were installed. All production work on the Honeywell systems was processed through the Compromise Compiler until the summer of 1963.
The Hybrid Compiler
The Hybrid Compiler was an interim device midway between the Compromise and the H-800 Compilers. The first half of the compilation was done on the H-800 computer using completed sections of the H-800 Compiler; the remainder was done on the Compromise Compiler. Advantages were conservation of machine time, better diagnostics and some liberalizing of the language rules.
The H-800 Compiler
The H-800 compiler, also known as HLOC, ran exclusively on the Honeywell System. Its usage became standard practice in 1964. It made possible additional language facilities.
The ELCA Compiler
The ELCA compiler gradually replaced HLOC during the years 1975-1977. It ran faster and generated better code and incorporated many useful language extensions. It had the option to generate assembly language (GMAP) which could be processed on Honeywell Series 66 machines.
In the 1980s MetLife "migrated" Met English programs from Honeywell hardware to IBM. (IBM hardware had been in use for COBOL programs for some time.) The Emulator read Honeywell machine code and interpreted each instruction on an MVS system. Some emulated programs were quite slow and this was not pursued as a long term solution.
The ELCA2 Compiler
MetLife developed a new compiler that generated IBM assembler code. The standard IBM assembler generated machine code from that. Versions of this compiler were used until the language was retired.