The idea behind this is to parse unary/binary operators into function calls with 1/2 operands. So the AST actually has a FunctionCall with the name "+". Function names may now be quoted operators, and thus you can also have function declarations with names such as "+". Resolving is *not* done in the parser for these function names, but rather every "+" is left as "+" (no matter what types it operates on, or what is in scope) by the parser (see later patches to InferTypes instead).
When parsing an occam source file, we automatically insert a bunch of PRAGMA TOCKEXTERNAL that define the default occam operators (e.g. + on INT) as external C functions (which they are!). The naming scheme for these C functions is standardised, and must be used by functions such as mulExprs (which bases the function on the type of its operands) and the new versions mulExprsInt (which are pegged to INT).
The Types module also has some new functions for dealing with operator-functions.
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