plotEqn() gains a ... arg

R/plotEqn.R

@@ -21,6 +21,7 @@
 #'      using the character string resulting from \code{\link{showEqn}}, modified so that the
 #'      \code{x}s are properly subscripted.
 #' @param solution logical; should the solution points for pairs of equations be marked?
+#' @param ... Other arguments passed to \code{plot}
 #' @return nothing; used for the side effect of making a plot
 #'
 #' @author Michael Friendly
@@ -45,9 +46,10 @@
 plotEqn <- function(A, b, vars, xlim, ylim,
                     col=1:nrow(A), lwd=2, lty=1,
                     axes=TRUE, labels=TRUE,
-                    solution=TRUE
+                    solution=TRUE,
+                    ...
 ) {
-
+  
   if (!is.numeric(A) || !is.matrix(A)) stop("A must be a numeric matrix")
   if (missing(b)) {
     b <- A[ , ncol(A)]   # assume last column of Ab
@@ -114,8 +116,8 @@ plotEqn <- function(A, b, vars, xlim, ylim,
   }
 
   for (i in 1:neq) {
-    if (i == 1) plot(xlim, ylim, type="n", xlab = vars[1], ylab = vars[2], xlim = xlim, ylim = ylim)
-
+    if (i == 1) plot(xlim, ylim, type="n", xlab = vars[1], ylab = vars[2], xlim = xlim, ylim = ylim, ...)
+    
     if (A[i, 2] == 0) {
       abline(v = b[i] / A[i, 1], col = col[i], lwd = lwd[i], lty = lty[i])
       y <- ylim

dev/plotEqn-test.R

@@ -2,6 +2,8 @@
 
 library(matlib)
 
+source(here::here("dev", "plotEqn.R"))
+
 A <- matrix(c( 1, 2, 0,
                -1, 2, 1), 3, 2) |>
   print()
@@ -11,9 +13,7 @@ b <- c(2, 1, 1)
 
 showEqn(A, b, vars = c("x", "y"), simplify = TRUE)
 
-plotEqn(A, b, vars = c("x", "y"),
-        cex.lab = 2,
-        solution = list(pch = 16))
+plotEqn(A, b, vars = c("x", "y"))
 
 # try to change the labels: doesn't work
 plotEqn(A, b, vars = c("x", "y"),