Conditional and FromStyleBlockAttr

[vvoovv]

claddingMaterial = PerBuilding(Value(Alternatives(
    FromAttr("roof:material", FromAttr.String, CladdingMaterials),
    Conditional(
        lambda roof: roof.footprint.getStyleBlockAttr("roofShape") == "flat",
        RandomWeighted(( ("concrete", 1), ("gravel", 1) ))
    ),
    Conditional(
        lambda roof: roof.footprint.getStyleBlockAttr("roofShape") == "dome",
        Constant("glass")
    ),
    FromStyleBlockAttr("claddingMaterial", FromStyleBlockAttr.Footprint)
)))

[vvoovv]

Condtional has to arguments:

• a condition
• a value

It returns the value if the conditions is True, otherwise it returns None.

[vvoovv]

It can be represented in PML as:

claddingMaterial:
    FromAttr("roof:material") |
    RandomWeighted( ("concrete", 1), ("gravel", 1) ) if item.footprint["roofShape"] == "flat" |
    glass if item.footprint["roofShape"] == "dome" |
    item.footprint["claddingMaterial"]
;           

[vvoovv]

How to represent it in blosm nodes?

[vvoovv]

Conditional node

Input sockets:

• condition
• value

Output sockets:

• value

[vvoovv]

From Style Block node

Input sockets:
no

Output sockets:

• value

Properties:

• item (a choice between "self", "footprint" and "parent")
• attribute (a list of popular style block attributes)

[vvoovv]

From OSM node

Input sockets:
no

Output sockets:

• value

Properties:

• OSM tag (a long list of the popular OSM tags)

[vvoovv]

Alternatives node

Input sockets (probably 7 values is enough):

• value 1
• value 2
• value 3
• value 4
• value 5
• value 6
• value 7

Output sockets:

• value

[vvoovv]

How to represent it in blosm nodes?

---

    FromAttr("roof:material", FromAttr.String, CladdingMaterials),

From OSM.value -> Alternatives.value 1

---

    Conditional(
        lambda roof: roof.footprint.getStyleBlockAttr("roofShape") == "flat",
        RandomWeighted(( ("concrete", 1), ("gravel", 1) ))
    ),

RandomWeighted.value -> Conditional.value
Conditional.value -> Alternatives.value 2

---

    Conditional(
        lambda roof: roof.footprint.getStyleBlockAttr("roofShape") == "dome",
        Constant("glass")
    ),
)))

CladdingMaterial.value -> Conditional.value
Conditional.value -> Alternatives.value 3

---

    FromStyleBlockAttr("claddingMaterial", FromStyleBlockAttr.Footprint)

From Style Block.value -> Alternatives.value 4

---

And finally:
Alternatives.value -> Roof.claddingMaterial

[vvoovv]

Per Building node

Input sockets:

• value

Output sockets:

• value

[vvoovv]

Per Footprint node

Input sockets:

• value

Output sockets:

• value

[polarkernel]

I do not really understand the term item in the condition. The proposition in PML is

glass if item.footprint["roofShape"] == "dome"

while the corrsponding Python code becomes

    Conditional(
        lambda roof: roof.footprint.getStyleBlockAttr("roofShape") == "dome",
        Constant("glass")
    ),

How can a translator find that the item is roof here? Where does this context come from?

[vvoovv]

Any variable can be used in the Python's lambda syntax:
lambda anything: anything is None

I'd suggest always use the variable item in the Python code.

[vvoovv]

To be continued at prochitecture/pml#6