Merge pull request #456 from Aman-Godara/replace_all

slice function's documentation made user friendly

Author: jvdp1

doc/specs/stdlib_strings.md

@@ -199,25 +199,21 @@ end program demo
 
 #### Description
 
-Extracts the characters from the defined region of the input string by taking strides.
+Extracts the characters from the defined region of the input string by taking strides.  
+Argument `first` and `last` defines this region for extraction by function `slice`.  
+Argument `stride` defines the magnitude and direction (+/-) of stride to be taken while extraction. 
+`stride` when given invalid value 0, is converted to +1.
 
-Deduction Process:
+Deduction Process:  
 Function first automatically deduces the optional arguments that are not provided by the user.  
-This process is independent of both input `string` and permitted indexes of Fortran.  
-Deduced `first` and `last` argument take +infinity or -infinity value whereas deduced `stride` argument takes +1 or -1 value.
-
-Validation Process:
-Argument `first` and `last` defines this region for extraction by function `slice`.  
-If the defined region is invalid i.e. region contains atleast one invalid index, `first` and 
-`last` are converted to first and last valid indexes in this defined region respectively, 
-if no valid index exists in this region an empty string is returned.  
-`stride` can attain both negative or positive values but when the only invalid value 
-0 is given, it is converted to 1.
-
-Extraction Process:
-After all this, extraction starts from `first` index and takes stride of length `stride`.  
-Extraction starts only if `last` index is crossable from `first` index with stride `stride` 
-and remains active until `last` index is crossed.  
+Deduced `first` and `last` argument take +infinity or -infinity value and deduced `stride` argument 
+takes value +1 or -1 depending upon the actual argument(s) provided by the user.  
+
+Extraction Process:  
+Extraction starts only if `last` is crossable from `first` with stride of `stride`.  
+Extraction starts from the first valid index in the defined region to take stride of `stride` 
+and ends when the last valid index in the defined region is crossed.  
+If no valid index exists in the defined region, empty string is returned.
 
 #### Syntax