detect alignment for function declarations

NEWS.md

@@ -9,6 +9,8 @@ editor_options:
 **Features**
 
 -   `filetype` `.qmd` is now supported, but not turned on by default (#931).
+-   alignment is now detected for function declaration in a similar way as for
+    function calls (#968).
 -   new R option `styler.ignore_alignment` controls if alignment should be
     detected (and preserved) or not (#932).
 

R/detect-alignment-utils.R

@@ -41,6 +41,38 @@ alignment_drop_comments <- function(pd_by_line) {
     compact()
 }
 
+
+#' Remove last expression
+#'
+#' In a *nest*, if the last token is an `expr`, the *nest* represents either
+#' an if, while or for statement or a function call. We don't call about that
+#' part, in fact it's important to remove it for alignment. See 'Examples'.
+#'
+#' @examples
+#' if (FALSE) {
+#'   call(
+#'     x = 12,
+#'     y =  3,
+#'   )
+#'
+#'   function(a = 33,
+#'            qq = 4) {
+#'     # we don't care about this part for alignment detection
+#'   }
+#' }
+#' @keywords internal
+alignment_drop_last_expr <- function(pds_by_line) {
+  # TODO could be skipped if we know it's not a function dec
+  pd_last_line <- pds_by_line[[length(pds_by_line)]]
+  last_two_lines <- pd_last_line$token[c(nrow(pd_last_line) - 1, nrow(pd_last_line))]
+  if (identical(last_two_lines, c("')'", "expr"))) {
+    pd_last_line <- pd_last_line[-nrow(pd_last_line), ]
+  }
+  pds_by_line[[length(pds_by_line)]] <- pd_last_line
+  pds_by_line
+}
+
+
 #' Ensure last pd has a trailing comma
 #'
 #' Must be after [alignment_ensure_no_closing_brace()] because if it comes after
@@ -83,9 +115,9 @@ alignment_col1_all_named <- function(relevant_pd_by_line) {
       return(FALSE)
     }
     x$token[3] == "expr" &&
-      x$token[1] %in% c("SYMBOL_SUB", "STR_CONST") &&
+      x$token[1] %in% c("SYMBOL_SUB", "STR_CONST", "SYMBOL_FORMALS") &&
       x$token[2] %in% c(
-        "EQ_SUB", "SPECIAL-IN", "LT", "GT", "EQ", "NE"
+        "EQ_SUB", "EQ_FORMALS", "SPECIAL-IN", "LT", "GT", "EQ", "NE"
       )
   }) %>%
     all()

R/detect-alignment.R

@@ -92,11 +92,13 @@ token_is_on_aligned_line <- function(pd_flat) {
     return(FALSE)
   }
 
-  pd_by_line <- alignment_drop_comments(pd_by_line) %>%
-    alignment_ensure_no_closing_brace(last_line_is_closing_brace_only)
+  pd_by_line <- alignment_drop_comments(pd_by_line)
   if (length(pd_by_line) < 1) {
     return(TRUE)
   }
+  pd_by_line <- alignment_drop_last_expr(pd_by_line) %>%
+    alignment_ensure_no_closing_brace(last_line_is_closing_brace_only)
+
   pd_by_line <- pd_by_line %>%
     alignment_ensure_trailing_comma()
   # now, pd only contains arguments separated by values, ideal for iterating

R/rules-spaces.R

@@ -16,10 +16,13 @@ set_space_around_op <- function(pd_flat, strict) {
   if (!any(op_after)) {
     return(pd_flat)
   }
-  if (sum(pd_flat$lag_newlines) > 2 &&
-    is_function_call(pd_flat) &&
-    any(pd_flat$token %in% c("EQ_SUB", "','")) &&
-    !getOption("styler.ignore_alignment", FALSE)
+  if (
+    !getOption("styler.ignore_alignment", FALSE) &&
+      (
+        (is_function_call(pd_flat) && sum(pd_flat$lag_newlines) > 2) ||
+          (is_function_dec(pd_flat) && sum(pd_flat$lag_newlines) > 1)
+      ) &&
+      any(pd_flat$token %in% c("EQ_SUB", "','", "EQ_FORMALS"))
   ) {
     is_on_aligned_line <- token_is_on_aligned_line(pd_flat)
   } else {

tests/testthat/alignment/fun-decs-in.R

@@ -0,0 +1,38 @@
+# aligned
+function(x   = NULL,
+         tt  = NULL,
+         ayz = NULL) {}
+
+
+# aligned
+k <- function(x   = NULL,
+              aq  = NULL,
+              ayz = NULL) {}
+
+
+# aligned, eq right
+function(x   =  2,
+         tt  =  1,
+         ayz = 99) {}
+
+# aligned, eq left
+function(x =    2,
+         tt =   1,
+         ayz = 99) {}
+
+
+# not aligned
+k <- function(x =   fish,
+              aq =     21,
+              ayz = t(322)) {}
+
+# aligned
+k <- function(x = flus(we),
+              aq =  x - 22, k = 22,
+              ayz = m(jk5), xfea =  3) {}
+
+
+# aligned
+k <- function(x = flus(we),
+              aq =  x - 22,    k = 22,
+              ayz = m(jk5), xfea =  3) {}

tests/testthat/alignment/fun-decs-out.R

@@ -0,0 +1,38 @@
+# aligned
+function(x   = NULL,
+         tt  = NULL,
+         ayz = NULL) {}
+
+
+# aligned
+k <- function(x   = NULL,
+              aq  = NULL,
+              ayz = NULL) {}
+
+
+# aligned, eq right
+function(x   =  2,
+         tt  =  1,
+         ayz = 99) {}
+
+# aligned, eq left
+function(x =    2,
+         tt =   1,
+         ayz = 99) {}
+
+
+# not aligned
+k <- function(x = fish,
+              aq = 21,
+              ayz = t(322)) {}
+
+# aligned
+k <- function(x = flus(we),
+              aq =  x - 22, k = 22,
+              ayz = m(jk5), xfea =  3) {}
+
+
+# aligned
+k <- function(x = flus(we),
+              aq =  x - 22,    k = 22,
+              ayz = m(jk5), xfea =  3) {}