Add some notes on shorthand

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jan 2023-10-12 23:43:10 -07:00
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@ -73,6 +73,7 @@ Each `Pattern` can contain `Ref`s pointing at other patterns, `Shape`s, and `Lab
## Glossary
- `Library`: A collection of named cells. OASIS or GDS "library" or file.
- "tree": Any Library which has only one topcell.
- `Pattern`: A collection of geometry, text labels, and reference to other patterns.
OASIS or GDS "Cell", DXF "Block".
- `Ref`: A reference to another pattern. GDS "AREF/SREF", OASIS "Placement".
@ -83,6 +84,92 @@ Each `Pattern` can contain `Ref`s pointing at other patterns, `Shape`s, and `Lab
- `annotation`: Additional metadata. OASIS or GDS "property".
## Design choices & shorthand
Most syntax and behavior should follow normal python conventions.
There are a few exceptions, either meant to catch common mistakes or to provide a shorthand for common operations:
### `Library` objects don't allow overwriting already-existing patterns
```python3
library['mycell'] = pattern0
library['mycell'] = pattern1 # Error! 'mycell' already exists and can't be overwritten
del library['mycell'] # We can explicitly delete it
library['mycell'] = pattern1 # And now it's ok to assign a new value
```
### Insert a newly-made hierarchical pattern (with children) into a layout
```python3
# Let's say we have a function which returns a new library containing one topcell (and possibly children)
tree = make_tree(...)
# To reference this cell in our layout, we have to add all its children to our `library` first:
top_name = tree.top() # get the name of the topcell
name_mapping = library.add(tree) # add all patterns from `tree`, renaming elgible conflicting patterns
new_name = name_mapping.get(top_name, top_name) # get the new name for the cell (in case it was auto-renamed)
my_pattern.ref(new_name, ...) # instantiate the cell
# This can be accomplished as follows
new_name = library << tree # Add `tree` into `library` and return the top cell's new name
my_pattern.ref(new_name, ...) # instantiate the cell
# In practice, you may do lots of
top_pattern.ref(lib << make_tree(...), ...)
```
### Place a hierarchical pattern into a layout, preserving its port info
```python3
# As above, we have a function that makes a new library containing one topcell (and possibly children)
tree = make_tree(...)
# We need to go get its port info to `place()` it into our existing layout,
new_name = library << tree # Add the tree to the library and return its name (see `<<` above)
abstract = library.abstract(tree) # An `Abstract` stores a pattern's name and its ports (but no geometry)
my_pattern.place(abstract, ...)
# With shorthand,
abstract = library <= tree
my_pattern.place(abstract, ...)
# or
my_pattern.place(library << make_tree(...), ...)
```
### Quickly add geometry, labels, or refs:
The long form for adding elements can be overly verbose:
```python3
my_pattern.shapes[layer].append(Polygon(vertices, ...))
my_pattern.labels[layer] += [Label('my text')]
my_pattern.refs[target_name].append(Ref(offset=..., ...))
```
There is shorthand for the most common elements:
```python3
my_pattern.polygon(layer=layer, vertices=vertices, ...)
my_pattern.rect(layer=layer, xctr=..., xmin=..., ymax=..., ly=...) # rectangle; pick 4 of 6 constraints
my_pattern.rect(layer=layer, ymin=..., ymax=..., xctr=..., lx=...)
my_pattern.path(...)
my_pattern.label(layer, 'my_text')
my_pattern.ref(target_name, offset=..., ...)
```
### Accessing ports
```python3
# Square brackets pull from the underlying `.ports` dict:
assert pattern['input'] is pattern.ports['input']
# And you can use them to read multiple ports at once:
assert pattern[('input', 'output')] == {
'input': pattern.ports['input'],
'output': pattern.ports['output'],
}
# But you shouldn't use them for anything except reading
pattern['input'] = Port(...) # Error!
has_input = ('input' in pattern) # Error!
```
## TODO