== CIVL IR ==

Language principles:
* CIVL-IR is a subset of CIVL-C.  A CIVL-IR program is a CIVL-C program, and has the same semantics.


Types:
* `$bool` : boolean type ($true and $false, unrelated to integers)
* `$char` : character type (Unicode characters, unrelated to integers)
* `$int` : mathematical integers
* `$real` : mathematical reals
* `$float<e,f>` : IEEE floating-point numbers e=significand bits, f=exponent bits
* `$herbrand<T>` : Herbrand type of non-Herbrand numeric type T
* `$proc` : process type
* `$bundle`: bundle type for sequence of any type (same as seq<T>?)
* `$heap` : heap type, for dynamic allocation
* `$range` : regular sequence of integers
* `$domain` : tuple of ranges
* `$mem` : set of memory locations
* `enum tag` : enumerated type
* `struct tag` : structured type
* `union tag` : union type
* `T[]` : array of T
* `void *` : pointer to anything
* `T *` : pointer to T
* `T(T1, ..., Tn)` : function consuming T1, ..., Tn and returning T
* `$seq<T>` : sequence of T
* `$set<T>` : set of T
* `$map<T1,T2>` : map from T1 to T2
* `$rel<T1, ..., Tn>` : relation,  set of n-tuples

Notes
* the difference between the array type and the sequence type is that elements of an array are addressable, i.e., one can form a pointer such as `&a[i]`.  This is not possible with sequences, sets, maps, or relations.
* the difference between the function type and map type: a function is really a procedure in the language, so it can modify the state as well as return a value.   A map is a logical partial function: it is defined on some subset of the domain type, it will always "return" the save value on a given input, it cannot modify the state.

Questions
* how to allocate an array
* how to initialize a variable (what are initial values?)
* how to go between sequences and arrays
* can you make types values? (reification)