Generate a JSON Schema for a chart config class

Emits the schema for one ChartConfig subclass: every property it declares or inherits, typed from its PropertySpec, plus a constant for the type discriminator. The result is self-contained – it validates a chart document on its own, without the family dispatcher.

Usage

chart_schema(cls, id, title, description, complete = FALSE)

Arguments

cls

S7 class: A ChartConfig subclass.

id

Character: The schema's $id URL.

title

Character: Human-readable schema title.

description

Character: What this chart is.

complete

Logical: If TRUE, emit the output-config kind, requiring every property.

Value

Named list: The JSON Schema, ready for jsonlite::toJSON().

Details

Two kinds, differing only in what they require:

• complete = FALSE (an input config) requires only type. The author sets a subset and the interface fills in the rest.

• complete = TRUE (an output config) requires every property, so a document that claims to be complete can be checked rather than trusted. The chart's own properties may still be null – "this chart has no title" is a fact worth recording – but the provenance maps may not: a document that cannot say where its values came from is not complete, whatever it claims.

Neither emits a default: what an interface fills in is not a fact about the document. Shared structural class rules are emitted in allOf, including inherited rules. Input schemas allow omitted values to be resolved by an interface; record schemas require every value. Numeric ordering, bound-column contents, and statistical/data-dependent checks still run during construction or compilation and cannot be inferred from JSON Schema validation alone.

Author

EDG

Examples

schema <- chart_schema(
  ScatterConfig,
  id = "https://schema.rtemis.org/chart/scatter/v1/schema.json",
  title = "rtemis ScatterConfig",
  description = "Scatter chart."
)
names(schema[["properties"]])

#>  [1] "type"             "dat_path"         "title"            "origin"          
#>  [5] "writer"           "legend_position"  "legend_placement" "x"               
#>  [9] "y"                "size"             "group"            "hover"           
#> [13] "fit_name"         "rug"              "fit"              "se"              
#> [17] "se_times"         "rsq"              "diagonal"         "diagonal_color"  
#> [21] "n_fit"            "fit_alpha"        "palette"          "square"          
#> [25] "equal_axes"       "pad"              "xlim"             "ylim"            
#> [29] "xlab"             "ylab"             "margin_top"       "margin_right"    
#> [33] "margin_bottom"    "margin_left"