Dynamic code generation

[Yuri05]

Sorry for the delay.
The variable fillLength is created during the call of .parseUpdateAestheticProperty when input argument is "fill"
To prevent potential copy/paste issues of very similar lines of code, most of the functions from aaa-utilities.R directly output R code as character strings (which are then transformed into expressions to be evaluated as actual R code using parse(text) and eval(expression).

Below shows the expression returned when the function .parseUpdateAestheticProperty is called with the arguments "fill" and ribbons.

> .parseUpdateAestheticProperty("fill", "ribbons")

expression(
fillVariable <- gsub("`", "", mapLabels$fill),
fillLength <- length(unique(mapData[, fillVariable])),
suppressMessages(
plotObject <- plotObject + ggplot2::scale_fill_manual(
values = .getAestheticValues(n = fillLength, selectionKey = plotConfiguration$ribbons$fill, aesthetic = "fill")
)
), 
if (isIncluded(fillVariable, "legendLabels")) {
plotObject <- plotObject + ggplot2::guides(fill = "none")
}
)

When the expression is wrapped by eval(), this code is evaluated and

• Creates the variable fillVariable, column name in the data linked to the fill property
• Creates the variable fillLength, number of unique values for the fill property (used for selecting the right number of colors)
• Update the fill properties of the plot plotObject
• Remove the legend if no mapping was actually defined

Note that changing "fill" by any other property name such as "color" or "alpha" would directly create an evaluated R code with all the property names changed to "color" or "alpha"

Originally posted by @pchelle in #338 (comment)

[IndrajeetPatil]

Did you mean to close this?

I don't see what the issue was.

[Yuri05]

The issue is here: #346