Re: pg_scanner - patch no.1

Just an FYI - I'm not ignoring your patches; I was away at PGConf.EU
last week and am very busy at the moment. They are on my TODO list
though.

Thanks.

On Sun, Oct 21, 2012 at 9:08 AM, Vladimir Kokovic
<vladimir(dot)kokovic(at)gmail(dot)com> wrote:
> Hi,
>
> This patch is my try to add lexical scanner for PostgreSQL SQL
> commands in Pgadmin source tree(prerequisite for patches no.2 and 3).
>
> The main reason why that is done is to scan and parse a SQL command in
> the same way
> like PostgreSQL server, but for limited number of parse functions.
>
> All scanner special cases are covered: TYPECAST(::), COLON_EQUALS(:=),
> DOT_DOT(..) and $foo$.
>
> Currently, three parsers implemented:
>
> 1. parse SQL command string for commands separated by ';'
> returns single linked list of commands
> struct myScannerNode *get_all_commands_cpp(const struct
> myScannerNode *head);
>
> 2. parse RULE SQL command and substitute source schema with target schema
> returns CREATE RULE SQL command with new schema name
> char *parse_rule_cpp(const struct myScannerNode *head, const
> char *rulename, const char *targetschema, const char *tablename);
>
> 3. parse TRIGGER SQL command and substitute source schema with target
> schema (pgadmin/utils/pasteTables.cpp)
> returns CREATE TRIGGER SQL command with new schema name
> char *parse_trigger_cpp(const struct myScannerNode *head, const
> char *targetschema);
>
>
> For all parsers 'scan_SQL_cpp' method is prerequisite which scan SQL
> command for tokens:
> returns single linked list of scan results (tokens)
> struct myScannerNode *scan_SQL_cpp(const char *command);
>
> If some error occurred during scan process, variable
> 'pgadmin_scanner_last_error' contains diagnostic message.
>
>
> *** This code snippet is from my pgadmin/frm/frmQuery.cpp ***
>
> /*
> * The scanner returns extra data about scanned tokens in this union type.
> * Note that this is a subset of the fields used in YYSTYPE of the bison
> * parsers built atop the scanner.
> */
> typedef union core_YYSTYPE
> {
> int ival; /* for integer literals */
> char *str; /* for identifiers and non-integer literals */
> const char *keyword; /* canonical spelling of keywords */
> } core_YYSTYPE;
>
>
> /*
> my token data struct
> */
> struct myScannerData {
> int loc;
> int token;
> core_YYSTYPE val;
> };
>
>
> /*
> my single linked list for scan results
> */
> struct myScannerNode {
> struct myScannerData data;
> struct myScannerNode *next;
> };
>
>
> //command offest from the beginning of SQL command string for each SQL command
> wxArrayInt locs;
>
> //SQL commands (queries)
> wxArrayString queries;
>
> //this is the first step which must be executed
> //scan_SQL_cpp returns single linked list of scan results (tokens)
>
> struct myScannerNode *head = scan_SQL_cpp(query.ToUTF8());
> if (head)
> {
> //parse scan results
> //get_all_commands_cpp returns single linked list of commands
> struct myScannerNode *result = get_all_commands_cpp(head);
>
> struct myScannerNode *current = result;
> if (current)
> {
> do
> {
> wxString x = wxString(current->data.val.str, wxConvUTF8);
> queries.Add(x);
> locs.Add(current->data.loc);
> current = current->next;
> } while (current != result);
> destroylist(result);
> }
> destroylist(head);
> }
>
>
>
> *** This code snippet is from my pgadmin/utils/pasteTables.cpp ***
>
> struct myScannerNode *head =
> scan_SQL_cpp(definition.mb_str(*srcrule->GetConnection()->GetConv()));
> if (head)
> {
> char *rule = parse_rule_cpp(
> head, qtname.ToAscii(), targetschema->GetIdentifier().ToAscii(),
> newtablename.ToAscii());
> if (rule)
> {
> newdefinition = wxString(rule, *targetschema->GetConnection()->GetConv());
> free(rule);
> }
> destroylist_cpp(head);
> }
>
>
> Best regards
> Vladimir Kokovic
> Belgrade, Serbia, 21.October 2012
>
>
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