adding regular expression to parse some edge cases. (#951)

The` .substitute_inputs` function substitute value for inputs either
input$ or input[[, but problem occurs when variable names that contain
periods or hyphens, such as `var.name `or` var-name` Although such
variable names are unconventional but they are acceptable . To ensure
that the `.substitute_inputs `function can work with a wider range of
variable names, I have made adjustments to the regular expressions
within the function so that it can correctly recognize and handle them.
This will allow for adherence to R's flexible naming conventions without
causing any errors during the substitution process.

for test regular expression
```

code_strings <- c("open_conn(username = input$username, username = input$use.rname, password = input$`pass-word`)",
                  "open_conn(username = input[[\"username\"]], password = input[[\"pass-word\"]])",
                  "open_conn(username = input$use.rname, password = input$`pass-word`)",
                  "open_conn(username = input[[\"use.rname\"]], password = input[[\"pass-word\"]])")

# Replace input$ with .()
code_strings <- gsub("input\\$(\\w+\\.?\\w*)", "\\.(\\1)", code_strings)
code_strings <- gsub("(input\\$)(`[^`]+`)", "\\.(\\2)", code_strings)

# Replace input[[ with .()
code_strings <- gsub("(input\\[\\[\")(\\w+\\.?\\w*)(\"\\]\\])", "\\.(\\2\\)", code_strings)
code_strings <- gsub("(input\\[\\[\")(\\w+\\-\\w+)\"\\]\\]", ".(`\\2`)", code_strings)
```

R/ddl-run.R

@@ -65,8 +65,13 @@ ddl_run <- function(input = list(),
   }
 
   code_strings <- vapply(code, deparse1, character(1L))
-  code_strings <- gsub("(input\\$)(\\w+)", "\\.(\\2\\)", code_strings)
-  code_strings <- gsub("(input\\[\\[\")(\\w+)(\"\\]\\])", "\\.(\\2\\)", code_strings)
+  # Replace input$ with .()
+  code_strings <- gsub("input\\$(\\w+\\.?\\w*)", "\\.(\\1)", code_strings)
+  code_strings <- gsub("(input\\$)(`[^`]+`)", "\\.(\\2)", code_strings)
+
+  # Replace input[[ with .()
+  code_strings <- gsub("(input\\[\\[\")(\\w+\\.?\\w*)(\"\\]\\])", "\\.(\\2\\)", code_strings)
+  code_strings <- gsub("(input\\[\\[\")(\\w+\\-\\w+)\"\\]\\]", ".(`\\2`)", code_strings)
 
   # Use bquote to obtain code with input values and masking values.
   as.expression(