Eliminate "class" from the parameter object

Author: aronatkins

R/params.R

@@ -9,8 +9,7 @@
 #' @param text Character vector containing the document text
 #' @param evaluate If TRUE, expression values embedded within the YAML will be
 #' evaluated. This is the default. When FALSE, parameters defined by an
-#' expression will have the parsed expression in its \code{value} field and
-#' \code{"expression"} in the \code{class} field.
+#' expression will have the parsed expression in its \code{value} field.
 #' 
 #' @return List of objects of class \code{knit_param} that correspond to the
 #'   parameters declared in the \code{params} section of the YAML front matter.
@@ -19,7 +18,6 @@
 #'   \describe{
 #'     \item{\code{name}}{The parameter name.}
 #'     \item{\code{value}}{The default value for the parameter.}
-#'     \item{\code{class}}{The R class names of the parameter's default value.}
 #'     \item{\code{expr}}{The R expression (if any) that yielded the default value.}
 #'   }
 #'
@@ -93,8 +91,7 @@ knit_params = function(text, evaluate = TRUE) {
 #' @param yaml Character vector containing the YAML text
 #' @param evaluate If TRUE, expression values embedded within the YAML will be
 #' evaluated. This is the default. When FALSE, parameters defined by an
-#' expression will have the parsed expression in its \code{value} field and
-#' \code{"expression"} in the \code{class} field.
+#' expression will have the parsed expression in its \code{value} field.
 #'
 #' @return List of objects of class \code{knit_param} that correspond to the
 #' parameters declared in the \code{params} section of the YAML. See
@@ -273,16 +270,6 @@ resolve_params = function(params, evaluate = TRUE) {
     # normalize parameter value (i.e. strip attributes, list -> vector)
     param$value = param_value(param$value)
 
-    # record parameter class (must be explicit for null values)
-    if (!is.null(param$value)) {
-      param$class = class(param$value)
-    } else {
-      if (is.null(param$class))
-        stop("no class field specified for YAML parameter '", name, "'",
-             " (fields with a value of null must specify an explicit class)",
-             call. = FALSE)
-    }
-
     # add knit_param class
     param = structure(param, class = "knit_param")
 

man/knit_params.Rd

@@ -10,8 +10,7 @@ knit_params(text, evaluate = TRUE)
 
 \item{evaluate}{If TRUE, expression values embedded within the YAML will be
 evaluated. This is the default. When FALSE, parameters defined by an
-expression will have the parsed expression in its \code{value} field and
-\code{"expression"} in the \code{class} field.}
+expression will have the parsed expression in its \code{value} field.}
 }
 \value{
 List of objects of class \code{knit_param} that correspond to the
@@ -21,7 +20,6 @@ List of objects of class \code{knit_param} that correspond to the
   \describe{
     \item{\code{name}}{The parameter name.}
     \item{\code{value}}{The default value for the parameter.}
-    \item{\code{class}}{The R class names of the parameter's default value.}
     \item{\code{expr}}{The R expression (if any) that yielded the default value.}
   }
 

man/knit_params_yaml.Rd

@@ -10,8 +10,7 @@ knit_params_yaml(yaml, evaluate = TRUE)
 
 \item{evaluate}{If TRUE, expression values embedded within the YAML will be
 evaluated. This is the default. When FALSE, parameters defined by an
-expression will have the parsed expression in its \code{value} field and
-\code{"expression"} in the \code{class} field.}
+expression will have the parsed expression in its \code{value} field.}
 }
 \value{
 List of objects of class \code{knit_param} that correspond to the

tests/testit/test-params.R

@@ -40,10 +40,10 @@ params:
 '
 )
 assert(params[[1]]$name == 'start')
-assert('Date' %in% params[[1]]$class)
+assert('Date' %in% class(params[[1]]$value))
 assert(params[[1]]$value == as.Date("2015-01-01"))
 assert(params[[2]]$name == 'end')
-assert('POSIXct' %in% params[[2]]$class)
+assert('POSIXct' %in% class(params[[2]]$value))
 assert(params[[2]]$value == as.POSIXct("2015-01-01 12:30:00", tz = "GMT"))
 
 
@@ -124,9 +124,9 @@ params:
 '
 )
 assert(!is.null(params[[1]]$expr))
-assert('Date' %in% params[[1]]$class)
+assert('Date' %in% class(params[[1]]$value))
 assert(params[[2]]$expr)
-assert('POSIXct' %in% params[[2]]$class)
+assert('POSIXct' %in% class(params[[2]]$value))
 assert(is.null(params[[3]]$expr))
 
 ## test handling of unevaluated expressions --------------------------------------------
@@ -138,7 +138,6 @@ params:
 ---
 ', evaluate = FALSE)
 assert(identical(params$today$expr, "Sys.Date()"))
-assert(identical(params$today$class, "expression"))
 assert(identical(class(params$today$value), "expression"))
 
 ## test handling of yaml parameters --------------------------------------------
@@ -149,10 +148,9 @@ params:
   today: !r Sys.Date()
 ')
 assert(params$x$value == 1)
-assert(identical(params$x$class, "integer"))
+assert(identical(class(params$x$value), "integer"))
 assert(identical(params$today$expr, "Sys.Date()"))
-assert('Date' %in% params$today$class)
-assert(identical(params$today$class, class(params$today$value)))
+assert('Date' %in% class(params$today$value))
 
 ## test handling of unevaluated yaml parameters --------------------------------------------
 
@@ -161,6 +159,5 @@ params:
   today: !r Sys.Date()
 ', evaluate = FALSE)
 assert(identical(params$today$expr, "Sys.Date()"))
-assert(identical(params$today$class, "expression"))
 assert(identical(class(params$today$value), "expression"))