New functions for strings package

packages/strings/strings.grnd

@@ -40,7 +40,7 @@ fun -char !findCharInstance -string &str -char &char -int &instance
     @return
     return $idx
 
-    @end    
+    @end
 endfun
 
 fun -string !mid -string &str -int &idx -int &len
@@ -74,7 +74,7 @@ fun -string !inBrackets -string &str -char &left -char &right -int &instance
     stdlnout $store
 endfun
 
-fun -string !matchStart -string &str -string &instr
+fun -bool !matchStart -string &str -string &instr
     getstrsize $instr &store
     pusharg $str
     pusharg 0 
@@ -119,4 +119,64 @@ fun -int !findStringInstance -string &str -string &instr -int &instance
     @end
     subtract $idx $len &idx
     return $idx
+endfun
+
+fun -string !removeLeft -string &string -int &num
+    getstrsize $string &len
+    set &ans ""
+    @loop
+        equal $num $len &store
+        if $store %end
+        getstrcharat $string $num &store
+        add $ans $store &ans
+        add $num 1 &num
+        jump %loop
+
+    @end
+    return $ans
+endfun
+
+fun -string !removeRight -string &string -int &num
+    getstrsize $string &len
+    subtract $len $num &len
+    set &ans ""
+    set &num 0
+    @loop
+        equal $num $len &store
+        if $store %end
+        getstrcharat $string $num &store
+        add $ans $store &ans
+        add $num 1 &num
+        jump %loop
+
+    @end
+    return $ans
+endfun
+
+fun -bool !contains -string &str -string &instr
+    getstrsize $str &len
+    getstrsize $instr &inlen
+    subtract $len $inlen &len
+    set &idx 0
+    
+    @loop
+        equal $idx $len &store
+        if $store %false
+        
+        pusharg $str
+        pusharg $idx
+        pusharg $inlen
+        call !mid &store
+
+        equal $store $instr &store
+        if $store %true
+
+        add $idx 1 &idx
+        jump %loop
+
+    @true
+    return true
+
+    @false
+    return false
 endfun