Uppdated string functions spec from JEP-14.

Author: springcomp

functions/find_first.yml

@@ -20,12 +20,15 @@ returns:
   desc: ''
 desc: |
   Given the `subject` string, `find_first()` returns the zero-based index of the first occurence where the `sub` substring appears in `subject` or `null` if it does not appear.
+  If either the `$subject` or the `$sub` argument is an empty string, `find_first()` return `null`.
 
   The `start` and `end` parameters are optional and allow restricting the range within `subject` in which `sub` must be found.
 
   * If `start` is omitted, it defaults to `0` (which is the start of the `subject` string).
   * If `end` is omitted, it defaults to `length(subject) - 1` (which is is the end of the `subject` string).
 
+  If not omitted, the `$start` and `$end` arguments are expected to be integers. Othewise, an error MUST be raised.
+
   Contrary to similar functions found in most popular programming languages, the `find_first()` function does not return `-1` if no occurrence of the substring can be found. Instead, it returns `null` for consistency reasons with how JMESPath behaves.
 examples:
   find_first:

functions/find_last.yml

@@ -9,37 +9,48 @@ args:
     type: [string]
     desc: 'Substring'
   optional: 
-    - name: pos
+    - name: start
       type: [number]
       desc: 'Position in the subject string where searching should start.'
+    - name: end
+      type: [number]
+      desc: 'Position in the subject string where searching should end.'
 returns:
   type: number
   desc: ''
 desc: |
-  Given the `subject` string, `find_last()` returns the zero-based index of the last occurence where the `sub` substring appears in `subject` or `null` if it does not appear.
+  Given the `$subject` string, `find_last()` returns the zero-based index of the last occurence where the `$sub` substring appears in `$subject` or `null` if it does not appear. If either the `$subject` or the `$sub` argument is an empty string, `find_last()` returns `null`.
+
+  The `$start` and `$end` parameters are optional and allow restricting to the slice `[$start:$end]` the range within `$subject` in which `$sub` must be found.
+
+  - If `$start` is omitted, it defaults to `0` (which is the start of the `$subject` string).
+  - If `$end` is omitted, it defaults to `length(subject)` (which is past the end of the `$subject` string).
 
-  The `pos` parameter is optional and allows restricting the maximum index within `subject` at which to search for `sub`.
-  If this is parameter omitted, it defaults to `length(subject) - 1` (which is is the end of the `subject` string).
+  If not omitted, the `$start` or `$end` arguments are expected to be integers. Otherwise, an error MUST be raised.
 
   Contrary to similar functions found in most popular programming languages, the `find_last()` function does not return `-1` if no occurrence of the substring can be found. Instead, it returns `null` for consistency reasons with how JMESPath behaves.
 examples:
   find_last:
     context: &subject subject string
     args: ['@', 'string']
     returns: 8.0
-  find_last_pos:
+  find_last_start:
     context: *subject
     args: ['@', 'string', '`8`']
     returns: 8.0
-  find_last_pos_ends_prematurely:
+  find_last_start_ends_prematurely:
+    context: *subject
+    args: ['@', 'string', '`8`', '`9`']
+    returns: null
+  find_last_start_after_occurrence:
     context: *subject
-    args: ['@', 'string', '`7`']
+    args: ['@', 'string', '`9`']
     returns: null
   find_last_second_occurrence:
     context: *subject
-    args: ['@', 's', '`8`']
+    args: ['@', 's', '`1`']
     returns: 8.0
   find_last_first_occurrence:
     context: *subject
-    args: ['@', 's', '`7`']
+    args: ['@', 's', '`0`', '`7`']
     returns: 0.0

functions/pad_left.yml

@@ -23,6 +23,8 @@ desc: |
   If present, it MUST have length 1, otherwise an error MUST be raised.
 
   If the `subject` string has length greater than or equal to `width`, it is returned unmodified.
+
+  If `$width` is not an integer, an error MUST be raised.
 examples:
   pad_left_less_than_length:
     context: &subject string

functions/pad_right.yml

@@ -23,6 +23,8 @@ desc: |
   If present, it MUST have length 1, otherwise an error MUST be raised.
 
   If the `subject` string has length greater than or equal to `width`, it is returned unmodified.
+
+  If `$width` is not an integer, an error MUST be raised.
 examples:
   pad_right_less_than_length:
     context: &subject string

functions/replace.yml

@@ -22,7 +22,7 @@ desc: |
   Given the `subject` string, `replace()` replaces ocurrences of the `old` substring with the `new` substring.
 
   The `count` optional parameter specifies how many occurrences of the `old` substring in `subject` are to be replaced.
-  If this parameter is omitted, all occurrences are replaced. If `count` is negative, an error MUST be raised.
+  If this parameter is omitted, all occurrences are replaced. If `count` is not an integer or is negative,
 
   The `replace()` function has no effect if `count` is `0`.
 examples:

functions/split.yml

@@ -23,7 +23,8 @@ desc: |
   string will be returned.
   
   The `count` optional parameter specifies the maximum number of split points within the `search` string.
-  If this parameter is omitted, all occurrences are split. If `count` is negative, an error MUST be raised.
+  If this parameter is omitted, all occurrences are split. If `count` is not an integer or is negative,
+  an error MUST be raised.
 
   If `count` is equal to `0`, `split()` returns an array containing a single element, the `subject` string.
 

jep-014-string-functions.md

@@ -58,7 +58,7 @@ Contrary to similar functions found in most popular programming languages, the `
 ```
 int find_last(string $subject, string $sub[, int $start[, int $end]])
 ```
-Given the `$subject` string, `find_last()` returns the zero-based index of the last occurence where the `$sub` substring appears in `$subject` or `null` if it does not appear. If either the `$subject` or the `$sub` argument is an empty string, `find_first()` returns `null`.
+Given the `$subject` string, `find_last()` returns the zero-based index of the last occurence where the `$sub` substring appears in `$subject` or `null` if it does not appear. If either the `$subject` or the `$sub` argument is an empty string, `find_last()` returns `null`.
 
 The `$start` and `$end` parameters are optional and allow restricting to the slice `[$start:$end]` the range within `$subject` in which `$sub` must be found.
 
@@ -67,7 +67,7 @@ The `$start` and `$end` parameters are optional and allow restricting to the sli
 
 If not omitted, the `$start` or `$end` arguments are expected to be integers. Otherwise, an error MUST be raised.
 
-Contrary to similar functions found in most popular programming languages, the `find_first()` function does not return `-1` if no occurrence of the substring can be found. Instead, it returns `null` for consistency reasons with how JMESPath behaves.
+Contrary to similar functions found in most popular programming languages, the `find_last()` function does not return `-1` if no occurrence of the substring can be found. Instead, it returns `null` for consistency reasons with how JMESPath behaves.
 
 ### Examples