Check if correct parameters are used.

R/RSAGA-core.R

@@ -857,6 +857,9 @@ rsaga.html.help = function(lib, module=NULL, use.program.folder = TRUE, env=rsag
 #' @param check.module.exists logical (default: `TRUE`): call [rsaga.module.exists()] to determine if the specified module can be called in the current SAGA installation
 #' @param warn logical (default: `TRUE`): for internal purposes - can be used to suppress warning messages generated by failed SAGA_CMD calls; currently used by [rsaga.get.lib.modules()] and related functions; see [options()] argument `warn` for details
 #' @param argsep character (default: `" "`; currently for internal use): defines the character symbol used as a separator between each argument name and argument value passed to `saga_cmd`. SAGA GIS 2.1.0 (RC1) seems to move toward `"="` as a separator, but `" "` still works and some modules (e.g. the used by `rsaga.pisr`) don't seem to work with `argsep="="`. Future releases of RSAGA may change the default `argsep` value and/or delete or ignore this argument and/or move it to [rsaga.env()].
+#'
+#' @param check.parameters logical(default: `TRUE`): Check if correct parameters are used.
+#'
 #' @param ... Additional arguments to be passed to [base::system()].
 #'
 #' @details This workhorse function establishes the interface between the SAGA command line program and R by submitting a system call. This is a low-level function that may be used for directly accessing SAGA; specific functions such as `rsaga.hillshade` are intended to be more user-friendly interfaces to the most frequently used SAGA modules. These higher-level interfaces support default values for the arguments and perform some error checking; they should therefore be preferred if available.
@@ -899,7 +902,7 @@ rsaga.geoprocessor = function(
     prefix = NULL, flags = ifelse(show.output.on.console,"q","s"), cores,
     env = rsaga.env(), display.command = FALSE, reduce.intern = TRUE,
     check.module.exists = TRUE, warn = options("warn")$warn,
-    argsep = " ", ... )
+    argsep = " ", check.parameters = TRUE, ... )
 {
 # Issue warning if using SAGA GIS version that has not been tested with RSAGA:
     if (!is.null(env$version)) {
@@ -988,6 +991,42 @@ rsaga.geoprocessor = function(
             }
         }
 
+        # Check parameters
+        if(check.parameters) {
+          # Some rsaga core calls need to suppress warnings
+          # related to non-zero exit codes of saga_cmd:
+          oldwarn = options("warn")$warn
+          on.exit(options(warn = oldwarn), add = TRUE)
+          options(warn = -1)
+
+          # Get console output
+          res <- system(paste0(command, " \"", module, "\""), intern = TRUE)
+          options(warn = oldwarn)
+
+          # Get parameters
+          i <- grep("Usage:", res)
+
+          # Extract parameter list
+          unlist(str_extract_all(res[i], "\\[(.*?)\\]")) %>%
+            str_remove("\\[-") %>%
+            str_remove("\\]") %>%
+            str_remove("<(.*?)>") %>%
+            str_remove("\\s") -> param_list
+
+          # Print error message
+          if(!all(names(params) %in% param_list)) {
+            #Get false parameter names
+            false_paramters <- names(params) %in% param_list
+            # Get all paramter names
+            paramters <- names(params)
+            stop(paste0("Wrong paramters used: ",
+                        paste(paramters[!false_paramter], collapse = " "),
+                        ". ",
+                        "Possible parameters:",
+                        paste(param_list, collapse = " ")))
+          }
+        }
+
         if (is.character(module)) module = shQuote(module)
         command = paste(command, module)
         if (length(param)>0) {