Changes between Version 28 and Version 29 of IR

Timestamp:

11/23/15 09:34:46 (10 years ago)

Author:

siegel

Comment:

--

IR

@@ -89 +89 @@
  * `T*` : pointer-to-T, subtype of above
 
-Type names:
-
-A type name is a syntactic element that names a type, together with possibly more information that makes the type "complete".  All of the names listed above are type names, such as `int[]`, but so is `int[n*m]`.  This is the same as in C.
+Type facts:
+
+**Pure types** contain no values anywhere in the type tree.  That is, there is no array length expression in the type.   The pure types are the static types of the CIVL-IR.  Each variable is declared to have some pure type.
+
+**Augmented types** include all the pure types plus possible length expressions.
+
+A **type name** is a syntactic element that names a (pure or augmented) type  Examples include `int[]` and `int[n*m]`.  This is the same as in C.
 
 The expression `$typefrom(T)`, where `T` is a type name, returns a value of type `$type` representing the type `T`.
@@ -97 +101 @@
 The expression `$typeof(e)`, where `e` is an expression, returns the type of `e`, a value of type `$type`.
 
-The expression `$initval(d)` takes a `$type` value `d` and returns the initial value for an object of type `d`.
+The expression `$initval(d)` takes a `$type` value `d` and returns the initial value for an object of type `d`.   The initial value of `$integer` and other primitive (non-compound) types is "undefined".   The initial value of `$integer[]` is an array of length 0 of `$integer`.  The initial value of `$real*` is the undefined pointer to `$real`.    The initial value of `$real[10]` is the array of length 10 in which each element is undefined.  In general, the initial value of an array of length n is the sequence of length n in which every element is the initial value of the element type of the array.   The initial value of a structure is the tuple in which each component is assigned the initial value for its type.
 
 Example: