addition multi-character trim function

Author: MrTeeett

doc/sql.extensions/README.trim

@@ -18,6 +18,9 @@ Format:
 	<trim character> ::=
 		<value expression>
 
+        <multi-character trim function> ::=
+                { BTRIM | LTRIM | RTRIM } <left paren> <trim source> [ <comma> <trim character> ] <right paren>
+
 Syntax Rules:
 	1) If <trim specification> is not specified, BOTH is assumed.
 	2) If <trim character> is not specified, ' ' is assumed.
@@ -36,3 +39,9 @@ B)
 		trim(rdb$relation_name) || ' is a system table'
 		from rdb$relations
 		where rdb$system_flag = 1;
+
+C)
+        select
+                ltrim(rdb$relation_name, 'RDB$')
+                from rdb$relations
+                where rdb$relation_name starting with 'RDB$';

src/common/keywords.cpp

@@ -505,6 +505,9 @@ static const TOK tokens[] =
 	{TOK_TRAPS, "TRAPS", true},
 	{TOK_TRIGGER, "TRIGGER", false},
 	{TOK_TRIM, "TRIM", false},
+    {TOK_BTRIM, "BTRIM", false},
+    {TOK_LTRIM, "LTRIM", false},
+    {TOK_RTRIM, "RTRIM", false},
 	{TOK_TRUE, "TRUE", false},
 	{TOK_TRUNC, "TRUNC", true},
 	{TOK_TRUSTED, "TRUSTED", true},

src/dsql/ExprNodes.cpp

@@ -12446,7 +12446,19 @@ ValueExprNode* TrimNode::dsqlPass(DsqlCompilerScratch* dsqlScratch)
 
 void TrimNode::setParameterName(dsql_par* parameter) const
 {
-	parameter->par_name = parameter->par_alias = "TRIM";
+    switch (where) {
+    case blr_trim_both:
+        parameter->par_name = parameter->par_alias = "TRIM";
+        break;
+    case blr_trim_leading:
+        parameter->par_name = parameter->par_alias = "LTRIM";
+        break;
+    case blr_trim_trailing:
+        parameter->par_name = parameter->par_alias = "RTRIM";
+        break;
+    default:
+        break;
+    }
 }
 
 bool TrimNode::setParameterType(DsqlCompilerScratch* dsqlScratch,

src/dsql/parse.y

@@ -694,6 +694,12 @@ using namespace Firebird;
 %token <metaNamePtr> UNICODE_CHAR
 %token <metaNamePtr> UNICODE_VAL
 
+// tokens added for Firebird 6.0
+
+%token <metaNamePtr> BTRIM
+%token <metaNamePtr> RTRIM
+%token <metaNamePtr> LTRIM
+
 // precedence declarations for expression evaluation
 
 %left	OR
@@ -4332,6 +4338,9 @@ keyword_or_column
 	| VARBINARY
 	| WINDOW
 	| WITHOUT
+        | BTRIM                                 // added in FB 6.0
+        | LTRIM
+        | RTRIM
 	;
 
 col_opt
@@ -8465,6 +8474,9 @@ of_first_last_day_part
 string_value_function
 	: substring_function
 	| trim_function
+        | btrim_function
+        | ltrim_function
+        | rtrim_function
 	| UPPER '(' value ')'
 		{ $$ = newNode<StrCaseNode>(blr_upcase, $3); }
 	| LOWER '(' value ')'
@@ -8505,6 +8517,34 @@ trim_function
 		{ $$ = newNode<TrimNode>(blr_trim_both, $3); }
 	;
 
+
+%type <valueExprNode> btrim_function
+btrim_function
+        : BTRIM '(' value ',' value ')'
+                { $$ = newNode<TrimNode>(blr_trim_both, $3, $5); }
+        | BTRIM '(' value ')'
+                { $$ = newNode<TrimNode>(blr_trim_both, $3); }
+        ;
+
+
+%type <valueExprNode> ltrim_function
+ltrim_function
+        : LTRIM '(' value ',' value ')'
+                { $$ = newNode<TrimNode>(blr_trim_leading, $3, $5); }
+        | LTRIM '(' value ')'
+                { $$ = newNode<TrimNode>(blr_trim_leading, $3); }
+        ;
+
+
+%type <valueExprNode> rtrim_function
+rtrim_function
+        : RTRIM '(' value ',' value ')'
+                { $$ = newNode<TrimNode>(blr_trim_trailing, $3, $5); }
+        | RTRIM '(' value ')'
+                { $$ = newNode<TrimNode>(blr_trim_trailing, $3); }
+        ;
+
+
 %type <blrOp> trim_specification
 trim_specification
 	: BOTH		{ $$ = blr_trim_both; }