/*
SQL Mode
By Ted Zuschlag <zuschlat@osshe.edu>
January 1997

	This is a hack based on epsilon's c_mode.
The code coloring is 98% effective.
(See function, is_sql_keyword, below.)

	Where possible, I simply re-used existing C functions.
Otherwise, I created lookalike SQL functions.
This SQL_MODE was designed for Oracle's enhanced ANSI SQL, called SQL*PLUS,
and their procedural extension of SQL, called PL/SQL.
(See functions, is_sql_keyword, and tag_plsql_script below.)

	SQL sentences are delimited by ; and /  .
SQL comments are either /*  * / just as in C or a leading   --  .
SQL*PLUS also permits the REMARK keyword to designate comment lines.
Quote delimiters are the single quote.

	I used Epsilon's tagging system in two different ways.
1) PL/SQL uses PROCEDURES and FUNCTIONS, and I tag these.
Arbitrarily, I decided to also tag the keywords, DECLARE, EXCEPTION, and
REMARK.  A different user may wish to omit the latter.
Such tagging occurs for file extensions, *.sql, *.sqw, *.osp, *.oss .
(*.OSP stands for Oracle Stored Procedure.  Thanks to author 
Steven Feuerstein for the idea!)

2) File extensions *.LST, use a different tagging function.  
It goes like this-- 
SQL*PLUS offers the DESCRIBE command, whose purpose is to describe
the layout (i.e. columns) of a table.  Repeated use of DESCRIBE <tablename> 
could be used to list a 'complete database schema'.  
Capture this SQL*PLUS session, and save as SCHEMA.LST (or whatever).  
Then have epsilon TAG_FILES on SCHEMA.LST.  Tagged, will be the <tablenames> 
the user specified when he dumped the 'complete database schema'.
In other words, tagged will be a 'wall chart' of the 'complete database schema'.

Revision history:
June 14 1997	Lugaru fixed a bug in the use of major_mode.
*/

#include "eel.h"
#include "c.h"
#include "colcode.h"

color_class text color_scheme "standard-color" green on black;

color_sql_from_here(safe)	// Move backward to the nearest line guaranteed
{							// to start outside any colored region, return pos.
	int pos, limit;			// We know safe is ok value to return.

	limit = point - safe;
	if (color_look_back && color_look_back < limit)
		limit = color_look_back;
	to_begin_line();
	pos = point;
	while ((in_c_comment(limit) & IN_OLD_COMMENT)
				       && search(-1, "/*")) {
		to_begin_line(); // move back out of an old-style comment
		pos = point;
	}
	point = pos;
	while (character(point - 2) == '\\') {	// don't stay on contin line
		point--;
		to_begin_line();
	}
	return point;
}

color_sql_range(from, to)	// recolor just this section
{							// last colored region may go past to
	int t = -1, talk, s;
	char pat[200];

	if (from >= to)
		return to;
	save_var point, matchstart, matchend;
	sql_init_color(from, to);
	point = from;
	talk = (to - from > 2000);	// show status during long delays
	save_var case_fold = 0;
	strcpy(pat, "/<*>|--|[\"']");
	if (!minimal_coloring)
		strcat(pat, "|[A-Za-z_][A-Za-z0-9_]*"
		       "|-?%.?[0-9]([A-Za-z0-9._]|[Ee]-)*");
	while (point < to) {
		if (!re_search(1, pat)) {
			t = size();
			break;
		}
		t = matchstart;
		switch (character(point - 1)) {		// check last char
		case '-':			// found // one-line comment
			nl_forward();
			set_character_color(t, point, color_class c_comment);
			break;
		case '*':			// found /* starting comment
			search(1, "*/");
			set_character_color(t, point, color_class c_comment);
			break;
		case '"':		// found a string literal
			point = t;
			re_search(1, "\"([^\"\\\n]|\\(.|\n))*[\"\n]");
			set_character_color(t, point, color_class c_number);
			if (get_character_color(point, (int *) 0, &s) == 
			    color_class c_number && s > to)  // fix up after
				sql_init_color(point, to = s); // quoted "'s
			break;
		case '\'':		// found a char const
			point = t;
			re_search(1, "\'([^\'\\\n]|\\(.|\n))*[\'\n]");
			set_character_color(t, point, color_class c_charconst);
			break;
		default:		// found identifier, kywd, or number
			set_character_color(t, point, sql_keyword_color(t));
			break;
		}
		if (talk)
			note("Coloring SQL program: %d%% complete...",
			     (point - from) * 100 / (to - from));
	}
	sql_init_color(to, t);
	if (talk)
		note("");
	return point;
}

sql_init_color(from, to)
{
	if (from < to)
		set_character_color(from, to, minimal_coloring
				    ? color_class c_function
				    : color_class c_punctuation);
}

sql_keyword_color(from)	// return color for "identifier" from here to point
{						// (something with alpha or digits)
	char buf[500];

	if (point - from > sizeof(buf) - 10)
		save_var point = from + sizeof(buf) - 10;
	buf[0] = '|';		// get identifier, between | chars
	grab(from, point, buf + 1);
	if (index("0123456789-.", buf[1]))
		return sql_number_color(buf + 1);
	strcpy(buf + point - from + 1, "|");
	if (is_sql_keyword(buf))
		return color_class c_function;
/*	if (color_class c_function != color_class c_identifier
	    && paren_follows())
		return color_class c_function;
	return color_class c_identifier;		see also colcode.e	*/
	return color_class c_number;
}

is_sql_keyword(p)		// is text in p (must be surrounded by |'s) a keyword?
char *p;
{
	if (strstr("|alter|index|table|add|modify|"
	"comment|on|table|column|commit|synonym|sysdate|"
	"create|or|replace|asc|desc|as|is|at|view|"
	"delete|from|where|and|drop|"
	"insert|into|values|group by|between|in|like|not|null|"
	"rename|select|all|distinct|group|order|by|of|for|truncate|"
	"having|update|set|union|intersect|current|CURRENT|RETURN|return"
	"start|PROCEDURE|FUNCTION|BEGIN|END|IF|THEN|ELSE|ELSIF|"
	"CREATE|OR|AS|IS|REPLACE|PACKAGE|BODY|PRAGMA|SUBTYPE|"
	"CURSOR|OPEN|FETCH|INTO|CLOSE|IN|OUT|NULL|LOOP|", p))
		return 1;
	return 0;
}

paren_follows() // is there whitespace followed by a "(" at point in buffer?
{		// if so, we assume it's a function name
	for (;; point++) {
		switch (curchar()) {
			case ' ': case '\t':	continue;
			case '(':		return 1;
			default:		return 0;
		}
	}
}

sql_number_color(s)	// return color for number in s
char *s;		// redefine to distinguish different bases
{
	s = s;		// silence eel's warning
	return color_class c_number;
}

char _sql_mode_name[] = "SQL";

command sql_mode()
{
	major_mode = _sql_mode_name;
	mouse_goes_to_tag = 1;
	strcpy (comment_begin, "REMARK ");
	strcpy (comment_end, " ");
	strcpy (comment_start, "^REMARK +");
	strcpy (comment_pattern, "^REMARK.+");
	comment_column = 0;
	tab_size = 3;
	want_backups = 1;			
	indent_with_tabs = 1;
	recolor_range = color_sql_range;	// set up coloring rules
	recolor_from_here = color_sql_from_here;
	if (want_code_coloring)		// maybe turn on coloring
		when_setting_want_code_coloring();
	make_mode();
/*	color_look_back = 0;
	want_code_coloring = 1;
*/
/*	mode_keys = sql_tab;		*/
/*	over_mode = 1;				*/
/*	display_column = 0;          scroll mode			*/
}

suffix_sql()  { sql_mode(); }
suffix_sqw()  { sql_mode(); }
suffix_sqx()  { sql_mode(); }
suffix_gqs()  { sql_mode(); }
suffix_osp()  { sql_mode(); }
suffix_oss()  { sql_mode(); }
suffix_sq1()  { sql_mode(); }
suffix_sq2()  { sql_mode(); }
suffix_sq3()  { sql_mode(); }

tag_plsql_script()
{
	char func[70];
	int start, opoint = point, ofold = case_fold;

	case_fold = 1;
	point = 0;
	while (re_search(1, "^[ \t]*(PROCEDURE |FUNCTION )"))
	{
		re_search(1, "([A-Z0-9_]+)");
		grab(start = find_group(1, 1), find_group(1, 0), func);
		add_tag(func, start);
	};
	case_fold = 1;
	point = 0;
	while (re_search(1, "^[ \t]*(%<%<)"))
	{
		re_search(1, "([A-Z0-9_]+)");
		grab(start = find_group(1, 1), find_group(1, 0), func);
		add_tag(func, start);
	};
	case_fold = 1;
	point = 0;
	while (re_search(1, "^[ \t]*(DECLARE|EXCEPTION)"))
	{
		grab(start = find_group(1, 1), find_group(1, 0), func);
		add_tag(func, start);
	};
	case_fold = 1;
	point = 0;
	while (re_search(1, "^[ \t]*(REMARK )"))
	{
		re_search(1, "([A-Z0-9_]+)");
		grab(start = find_group(1, 1), find_group(1, 0), func);
		add_tag(func, start);
	};

	case_fold = ofold;
	point = opoint;
}	

tag_suffix_sql()		/* tag pl/sql proc and func calls */
{
	tag_plsql_script();
}
tag_suffix_sqw()		/* tag pl/sql proc and func calls */
{
	tag_plsql_script();
}
tag_suffix_osp()		/* tag pl/sql proc and func calls */
{
	tag_plsql_script();
}
tag_suffix_oss()		/* tag pl/sql proc and func calls */
{
	tag_plsql_script();
}

tag_suffix_lst()		/* tag pl/sql proc and func calls */
{
	char func[70];
	int start, opoint = point, ofold = case_fold;

	case_fold = 1;
	point = 0;
	while (re_search(1, "^[A-Za-z0-9: ]+<Rangle>[ \t]*(desc )"))
	{
		re_search(1, "([A-Za-z0-9_]+)");
		grab(start = find_group(1, 1), find_group(1, 0), func);
		add_tag(func, start);
	};

	case_fold = ofold;
	point = opoint;
}