Changeset ad24245


Ignore:
Timestamp:
Mar 1, 2023, 5:45:55 PM (13 months ago)
Author:
Michael Brooks <mlbrooks@…>
Branches:
ADT, ast-experimental, master
Children:
997324c
Parents:
601bd9e
Message:

Add comments about arpk internals.

File:
1 edited

Legend:

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  • libcfa/src/containers/array.hfa

    r601bd9e rad24245  
    99
    1010
    11 //
    12 // Single-dim array sruct (with explicit packing and atom)
    13 //
    14 
     11//
     12// The `array` macro is the public interface.
     13// It computes the type of a dense (trivially strided) array.
     14// All user-declared objects are dense arrays.
     15//
     16// The `arpk` (ARray with PacKing info explicit) type is, generally, a slice with _any_ striding.
     17// This type is meant for internal use.
     18// CFA programmers should not instantiate it directly, nor access its field.
     19// CFA programmers should call ?[?] on it.
     20// Yet user-given `array(stuff)` expands to `arpk(stuff')`.
     21// The comments here explain the resulting internals.
     22//
     23// Just as a plain-C "multidimesional" array is really array-of-array-of-...,
     24// so does arpk generally show up as arpk-of-arpk-of...
     25//
     26// In the example of `array(float, 3, 4, 5) a;`,
     27// `typeof(a)` is an `arpk` instantiation.
     28// These comments explain _its_ arguments, i.e. those of the topmost `arpk` level.
     29//
     30// [N]    : the number of elements in `a`; 3 in the example
     31// S      : carries the stride size (distance in bytes between &myA[0] and &myA[1]), in sizeof(S);
     32//          same as Timmed when striding is trivial, same as Timmed in the example
     33// Timmed : (T-immediate) the inner type; conceptually, `typeof(a)` is "arpk of Timmed";
     34//          array(float, 4, 5) in the example
     35// Tbase  : (T-base) the deepest element type that is not arpk; float in the example
     36//
    1537forall( [N], S & | sized(S), Timmed &, Tbase & ) {
     38
     39    //
     40    // Single-dim array sruct (with explicit packing and atom)
     41    //
    1642    struct arpk {
    1743        S strides[N];
     
    184210#endif
    185211
    186 // Available for users to work around Trac #265
    187 // If `a[...0...]` isn't working, try `a[...ix0...]` instead.
    188 
    189 #define ix0 ((ptrdiff_t)0)
     212// Available for users to work around Trac #265//
     213// Single-dim array sruct (with explicit packing and atom)
     214//
     215
    190216
    191217
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