R: Parse interpolated variables from SQL.

sqlParseVariables {DBI} | R Documentation

## Parse interpolated variables from SQL.

### Description

If you're implementing a backend that uses non-ANSI quoting or commenting rules, you'll need to implement a method for `sqlParseVariables` that calls `sqlParseVariablesImpl` with the appropriate quote and comment specifications.

### Usage

    sqlParseVariables(conn, sql, ...)

    sqlCommentSpec(start, end, endRequired)

    sqlQuoteSpec(start, end, escape = "", doubleEscape = TRUE)

    sqlParseVariablesImpl(sql, quotes, comments)

### Arguments

`sql` | SQL to parse (a character string)
`start, end` | Start and end characters for quotes and comments
`endRequired` | Is the ending character of a comment required?
`escape` | What character can be used to escape quoting characters? Defaults to `""`, i.e. nothing.
`doubleEscape` | Can quoting characters be escaped by doubling them? Defaults to `TRUE`.
`quotes` | A list of `QuoteSpec` calls defining the quoting specification.
`comments` | A list of `CommentSpec` calls defining the commenting specification.

### Examples

    # Use [] for quoting and no comments
    sqlParseVariablesImpl("[?a]",
      list(sqlQuoteSpec("[", "]", "\\", FALSE)),
      list()
    )

    # Standard quotes, use # for commenting
    sqlParseVariablesImpl("# ?a\n?b",
      list(sqlQuoteSpec("'", "'"), sqlQuoteSpec('"', '"')),
      list(sqlCommentSpec("#", "\n", FALSE))
    )

[Package DBI version 0.6-1 Index]