Enable perl by default, output non-default options in comments

NEWS.md

@@ -1,12 +1,16 @@
-## regexplain 0.1.x
-
-### 0.1.6
+## regexplain 0.2
 
 * Added "Templates" button that opens a dialog to import regex patterns
   (initially) sourced from <https://projects.lukehaas.me/regexhub>.
 * Added "Introduction", "Try These Examples" and "Resources" tabs to
   the standard gadget Help tab.
-* Several bugfixes and tests were added around unicode character escaping within the gadget.
+* Several bugfixes and tests were added around unicode character escaping within
+  the gadget. 
+* Enable `perl` mode by default in gadget (consistent with `stringr` and most
+  regexes in the wild, but not base R). Write out selected options as comments
+  when not consistent with base R when returning pattern from gadget.
+
+## regexplain 0.1.x
 
 ### 0.1.5
 

R/regex_gadget.R

@@ -76,7 +76,7 @@ regex_gadget <- function(text = NULL,
                   HTML('<span style="color: #5cb85c;">Fixed/Literal</span>'),
                   HTML('<span style="color: #f0ad4e;">Perl Style</span>'),
                   HTML('<span style="color: #f0ad4e;">Use Bytes</span>')),
-                selected = c('text_break_lines')
+                selected = c('text_break_lines', 'perl')
               )
             ),
             tags$div(
@@ -675,6 +675,11 @@ regex_gadget <- function(text = NULL,
     observeEvent(input$done, {
       if (pattern() != "") {
         pattern <- paste0('pattern <- "', escape_backslash(pattern()), '"')
+        if (any(c("perl", "fixed", "ignore.case", "useBytes") %in% input$regex_options)) {
+          options <- input$regex_options[input$regex_options != "text_break_lines"]
+          options <- paste0(options, "=TRUE", collapse = ", ")
+          pattern <- paste(pattern, "#", options)
+        }
         if ("regexFn_replacement" %in% names(input) && replacement() != "") {
           pattern <- paste0(
             pattern, "\n",