Fix #139, add API for accessing notebook metadata programmatically

src/QuartoNotebookWorker/src/NotebookState.jl

@@ -6,6 +6,7 @@ import ..QuartoNotebookWorker
 
 const PROJECT = Ref("")
 const OPTIONS = Ref(Dict{String,Any}())
+const CELL_OPTIONS = Ref(Dict{String,Any}())
 
 function __init__()
     if ccall(:jl_generating_output, Cint, ()) == 0

src/QuartoNotebookWorker/src/QuartoNotebookWorker.jl

@@ -5,6 +5,9 @@ module QuartoNotebookWorker
 export Cell
 export expand
 
+export cell_options
+export notebook_options
+
 
 walk(x, _, outer) = outer(x)
 walk(x::Expr, inner, outer) = outer(Expr(x.head, map(inner, x.args)...))
@@ -94,5 +97,6 @@ include("cell_expansion.jl")
 include("render.jl")
 include("utilities.jl")
 include("ojs_define.jl")
+include("notebook_metadata.jl")
 
 end

src/QuartoNotebookWorker/src/notebook_metadata.jl

@@ -0,0 +1,18 @@
+"""
+    notebook_options() -> Dict{String,Any}
+
+All Quarto options that are either set by the user within their notebook
+frontmatter, or implicitly set by Quarto itself at runtime. Note that this is a
+copy of the options used internally and mutation will not affect any other parts
+of notebook evaluation.
+"""
+notebook_options() = deepcopy(NotebookState.OPTIONS[])
+
+"""
+    cell_options() -> Dict{String,Any}
+
+The options for the current cell being evaluated. This is a copy of the options
+used internally and mutation will not affect any other parts of notebook
+evaluation.
+"""
+cell_options() = deepcopy(NotebookState.CELL_OPTIONS[])

src/QuartoNotebookWorker/src/render.jl

@@ -39,6 +39,7 @@ function _render_thunk(
     is_expansion_ref::Ref{Bool} = Ref(false);
     inline::Bool,
 )
+    NotebookState.CELL_OPTIONS[] = cell_options
     captured, display_results = with_inline_display(thunk, cell_options)
 
     # Attempt to expand the cell. This requires the cell result to have a method

test/examples/notebook_metadata.qmd

@@ -0,0 +1,53 @@
+---
+title: Notebook Metadata
+julia:
+    env: ["KEY=value"]
+---
+
+```{julia}
+import QuartoNotebookWorker
+```
+
+```{julia}
+let options = QuartoNotebookWorker.notebook_options()
+    options["format"]["metadata"]["julia"]["env"] == ["KEY=value"]
+end
+```
+
+```{julia}
+#| key: value
+let options = QuartoNotebookWorker.cell_options()
+    options["key"] == "value"
+end 
+```
+
+```{julia}
+struct CustomStruct
+    content::Any
+
+    function CustomStruct(content)
+        new([
+            QuartoNotebookWorker.Cell(
+                n.thunk;
+                code = get(n, :code, nothing),
+                options = get(n, :options, Dict()),
+            ) for n in content
+        ])
+    end
+end
+QuartoNotebookWorker.expand(cs::CustomStruct) = cs.content
+```
+
+```{julia}
+#| key: value_1
+static_options = QuartoNotebookWorker.cell_options()
+CustomStruct([
+    (;
+        thunk = function ()
+            options = QuartoNotebookWorker.cell_options()
+            static_options["key"] == "value_1" && options["key"] == "value_2"
+        end,
+        options = Dict{String,Any}("key" => "value_2"),
+    ),
+])
+```

test/testsets/notebook_metadata.jl

@@ -0,0 +1,11 @@
+include("../utilities/prelude.jl")
+
+test_example(joinpath(@__DIR__, "../examples/notebook_metadata.qmd")) do json
+    cells = json["cells"]
+
+    cell = cells[4]
+    @test cell["outputs"][1]["data"]["text/plain"] == "true"
+
+    cell = cells[11]
+    @test cell["outputs"][1]["data"]["text/plain"] == "true"
+end