d97e33b · urbit.org · git.iko.soy

git.iko.soy/urbit.org

on master help sign in

Merge pull request #928 from sigilante/master

d97e33bDavid Kerschner6 years ago

tutorials/vere/jetting.md+11−2

compare with master

unifiedsplit

@@ -534,6 +534,8 @@ If you need to get the size

534 u3r_met(3, a);

535```

536

537+Cells have their own set of characteristic functions for accessing interior nouns: `u3r_cell`, `u3r_trel`, `u3r_qual`, `u3h`, `u3t`, and the like.

538+

537The actual meat of the function is up to you. What is it supposed to do?

539The actual meat of the function is up to you. What is it supposed to do?

538

540

539Now we move on to return semantics.

541Now we move on to return semantics.

@@ -600,7 +602,7 @@ ending your C code with

600 return(123);

602 return(123);

601```

603```

602

604

603−is wrong and will result in a dojo error because you are returning a single atom, instead of a list of three atoms.

605+is wrong and will result in a dojo error because you are returning a single atom, instead of a tuple containing three atoms.

604

606

605Instead do one of these:

607Instead do one of these:

606

608

@@ -610,7 +612,7 @@ Instead do one of these:

610 return(u3nq(a, b, c, d)); // for four atoms

612 return(u3nq(a, b, c, d)); // for four atoms

611```

613```

612

614

613−If you need to return a longer list, you can compose your own. Look

615+If you need to return a longer tuple, you can compose your own. Look

614at the definitions of these three functions and you will see that they

616at the definitions of these three functions and you will see that they

615are just recursive calls to the cell constructor `u3i_cell()` e.g.

617are just recursive calls to the cell constructor `u3i_cell()` e.g.

616

618

@@ -618,6 +620,13 @@ are just recursive calls to the cell constructor `u3i_cell()` e.g.

618 u3i_cell(a, u3i_cell(b, u3i_cell(c, d));

620 u3i_cell(a, u3i_cell(b, u3i_cell(c, d));

619```

621```

620

622

623+This implies that, to create a list instead of a cell, you will need to append

624+`u3_nul` to the appropriately-sized tuple constructor:

625+

626+```c

627+ return(u3nt(a, b, u3_nul)); // for two atoms as a list

628+```

629+

621Understanding the memory model, allocation, freeing, and ownership ('transfer' vs 'retain' semantics) is important. Some info is available at [Nouns](@/docs/tutorials/vere/nouns.md).

630Understanding the memory model, allocation, freeing, and ownership ('transfer' vs 'retain' semantics) is important. Some info is available at [Nouns](@/docs/tutorials/vere/nouns.md).

622

631

623## Compile the C code

632## Compile the C code