Improved parsing and prefix/suffix matching using a `remainder`

parameter

37 files changed, 528 insertions, 178 deletions

diff --git a/CHANGES.md b/CHANGES.md
index d6e1e24f..0cd6df3a 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -10,10 +10,17 @@
   number and exit.
 - Added `tomo --prefix` to print the Tomo install prefix.
 - Sets now support infix operations for `and`, `or`, `xor`, and `-`.
-- Added Path.sibling().
-- Added Path.has_extension().
-- Added Table.with_fallback().
-- Added Int*.get_bit() and Byte.get_bit().
+- Added `Path.sibling()`.
+- Added `Path.has_extension()`.
+- Added `Table.with_fallback()`.
+- Added `Int*.get_bit()` and `Byte.get_bit()`.
+- Added `Byte.parse()` to parse bytes from text.
+- Added optional `remainder` parameter to `parse()` methods, which (if
+  non-none) receives the remaining text after the match. If `none`, the match
+  will fail unless it consumes the whole text.
+- Added optional `remainder` parameter to `Text.starts_with()` and
+  `Text.ends_with()` to allow you to get the rest of the text without two
+  function calls.
 - Improved space efficiency of Text that contains non-ASCII codepoints.
 - Doctests now use equality checking instead of converting to text.
 - Fixed the following bugs:
diff --git a/api/api.md b/api/api.md
index 9711ab44..09d24e73 100644
--- a/api/api.md
+++ b/api/api.md
@@ -186,7 +186,7 @@ sleep(1.5)
 ## Bool.parse
 
 ```tomo
-Bool.parse : func(text: Text -> Bool?)
+Bool.parse : func(text: Text, remainder: &Text? = none -> Bool?)
 ```
 
 Converts a text representation of a boolean value into a boolean. Acceptable boolean values are case-insensitive variations of `yes`/`no`, `y`/`n`, `true`/`false`, `on`/`off`.
@@ -194,6 +194,7 @@ Converts a text representation of a boolean value into a boolean. Acceptable boo
 Argument | Type | Description | Default
 ---------|------|-------------|---------
 text | `Text` | The string containing the boolean value.  | -
+remainder | `&Text?` | If non-none, this argument will be set to the remainder of the text after the matching part. If none, parsing will only succeed if the entire text matches.  | `none`
 
 **Return:** `yes` if the string matches a recognized truthy boolean value; otherwise return `no`.
 
@@ -207,6 +208,14 @@ text | `Text` | The string containing the boolean value.  | -
 >> Bool.parse("???")
 = none : Bool?
 
+>> Bool.parse("yesJUNK")
+= none : Bool?
+remainder : Text
+>> Bool.parse("yesJUNK", &remainder)
+= yes : Bool?
+>> remainder
+= "JUNK"
+
 ```
 
 # Byte
@@ -293,7 +302,7 @@ high | `Byte` | The upper bound to check (inclusive).  | -
 ## Byte.parse
 
 ```tomo
-Byte.parse : func(text: Text -> Byte?)
+Byte.parse : func(text: Text, remainder: &Text? = none -> Byte?)
 ```
 
 Parse a byte literal from text.
@@ -301,6 +310,7 @@ Parse a byte literal from text.
 Argument | Type | Description | Default
 ---------|------|-------------|---------
 text | `Text` | The text to parse.  | -
+remainder | `&Text?` | If non-none, this argument will be set to the remainder of the text after the matching part. If none, parsing will only succeed if the entire text matches.  | `none`
 
 **Return:** The byte parsed from the text, if successful, otherwise `none`.
 
@@ -308,9 +318,17 @@ text | `Text` | The text to parse.  | -
 **Example:**
 ```tomo
 >> Byte.parse("5")
-= Byte(5)?
+= Byte(5) : Byte?
 >> Byte.parse("asdf")
-= none
+= none : Byte?
+
+>> Byte.parse("123xyz")
+= none : Byte?
+remainder : Text
+>> Byte.parse("123xyz", &remainder)
+= Byte(123) : Byte?
+>> remainder
+= "xyz"
 
 ```
 ## Byte.to
@@ -614,7 +632,7 @@ stop if i == 10
 ## Int.parse
 
 ```tomo
-Int.parse : func(text: Text -> Int?)
+Int.parse : func(text: Text, remainder: &Text? = none -> Int?)
 ```
 
 Converts a text representation of an integer into an integer.
@@ -622,6 +640,7 @@ Converts a text representation of an integer into an integer.
 Argument | Type | Description | Default
 ---------|------|-------------|---------
 text | `Text` | The text containing the integer.  | -
+remainder | `&Text?` | If non-none, this argument will be set to the remainder of the text after the matching part. If none, parsing will only succeed if the entire text matches.  | `none`
 
 **Return:** The integer represented by the text. If the given text contains a value outside of the representable range or if the entire text can't be parsed as an integer, `none` will be returned.
 
@@ -633,6 +652,14 @@ text | `Text` | The text containing the integer.  | -
 >> Int.parse("0xFF")
 = 255 : Int?
 
+>> Int.parse("123xyz")
+= none
+remainder : Text
+>> Int.parse("123xyz", &remainder)
+= 123 : Int?
+>> remainder
+= "xyz"
+
 # Can't parse:
 >> Int.parse("asdf")
 = none : Int?
@@ -2250,7 +2277,7 @@ y | `Num` | The direction towards which to find the next representable value.  |
 ## Num.parse
 
 ```tomo
-Num.parse : func(text: Text -> Num?)
+Num.parse : func(text: Text, remainder: &Text? = none -> Num?)
 ```
 
 Converts a text representation of a number into a floating-point number.
@@ -2258,6 +2285,7 @@ Converts a text representation of a number into a floating-point number.
 Argument | Type | Description | Default
 ---------|------|-------------|---------
 text | `Text` | The text containing the number.  | -
+remainder | `&Text?` | If non-none, this argument will be set to the remainder of the text after the matching part. If none, parsing will only succeed if the entire text matches.  | `none`
 
 **Return:** The number represented by the text or `none` if the entire text can't be parsed as a number.
 
@@ -2265,9 +2293,17 @@ text | `Text` | The text containing the number.  | -
 **Example:**
 ```tomo
 >> Num.parse("3.14")
-= 3.14
+= 3.14 : Num?
 >> Num.parse("1e3")
-= 1000
+= 1000 : Num?
+
+>> Num.parse("1.5junk")
+= none : Num?
+remainder : Text
+>> Num.parse("1.5junk", &remainder)
+= 1.5 : Num?
+>> remainder
+= "junk"
 
 ```
 ## Num.percent
@@ -4218,7 +4254,7 @@ text | `Text` | The text from which to extract codepoint names.  | -
 ## Text.ends_with
 
 ```tomo
-Text.ends_with : func(text: Text, suffix: Text -> Bool)
+Text.ends_with : func(text: Text, suffix: Text, remainder: &Text? = none -> Bool)
 ```
 
 Checks if the `Text` ends with a literal suffix text.
@@ -4227,6 +4263,7 @@ Argument | Type | Description | Default
 ---------|------|-------------|---------
 text | `Text` | The text to be searched.  | -
 suffix | `Text` | The literal suffix text to check for.  | -
+remainder | `&Text?` | If non-none, this value will be set to the rest of the text up to the trailing suffix. If the suffix is not found, this value will be set to the original text.  | `none`
 
 **Return:** `yes` if the text has the target, `no` otherwise.
 
@@ -4235,6 +4272,11 @@ suffix | `Text` | The literal suffix text to check for.  | -
 ```tomo
 >> "hello world".ends_with("world")
 = yes
+remainder : Text
+>> "hello world".ends_with("world", &remainder)
+= yes
+>> remainder
+= "hello "
 
 ```
 ## Text.from
@@ -4712,7 +4754,7 @@ delimiters | `Text` | A text containing delimiters to use for splitting the text
 ## Text.starts_with
 
 ```tomo
-Text.starts_with : func(text: Text, prefix: Text -> Bool)
+Text.starts_with : func(text: Text, prefix: Text, remainder: &Text? = none -> Bool)
 ```
 
 Checks if the `Text` starts with a literal prefix text.
@@ -4721,6 +4763,7 @@ Argument | Type | Description | Default
 ---------|------|-------------|---------
 text | `Text` | The text to be searched.  | -
 prefix | `Text` | The literal prefix text to check for.  | -
+remainder | `&Text?` | If non-none, this value will be set to the rest of the text after the prefix. If the prefix is not found, this value will be set to the original text.  | `none`
 
 **Return:** `yes` if the text has the given prefix, `no` otherwise.
 
@@ -4729,6 +4772,11 @@ prefix | `Text` | The literal prefix text to check for.  | -
 ```tomo
 >> "hello world".starts_with("hello")
 = yes
+remainder : Text
+>> "hello world".starts_with("hello", &remainder)
+= yes
+>> remainder
+= " world"
 
 ```
 ## Text.title
diff --git a/api/booleans.md b/api/booleans.md
index d45be505..ab08909d 100644
--- a/api/booleans.md
+++ b/api/booleans.md
@@ -6,7 +6,7 @@
 ## Bool.parse
 
 ```tomo
-Bool.parse : func(text: Text -> Bool?)
+Bool.parse : func(text: Text, remainder: &Text? = none -> Bool?)
 ```
 
 Converts a text representation of a boolean value into a boolean. Acceptable boolean values are case-insensitive variations of `yes`/`no`, `y`/`n`, `true`/`false`, `on`/`off`.
@@ -14,6 +14,7 @@ Converts a text representation of a boolean value into a boolean. Acceptable boo
 Argument | Type | Description | Default
 ---------|------|-------------|---------
 text | `Text` | The string containing the boolean value.  | -
+remainder | `&Text?` | If non-none, this argument will be set to the remainder of the text after the matching part. If none, parsing will only succeed if the entire text matches.  | `none`
 
 **Return:** `yes` if the string matches a recognized truthy boolean value; otherwise return `no`.
 
@@ -27,4 +28,12 @@ text | `Text` | The string containing the boolean value.  | -
 >> Bool.parse("???")
 = none : Bool?
 
+>> Bool.parse("yesJUNK")
+= none : Bool?
+remainder : Text
+>> Bool.parse("yesJUNK", &remainder)
+= yes : Bool?
+>> remainder
+= "JUNK"
+
 ```
diff --git a/api/booleans.yaml b/api/booleans.yaml
index 0831ac18..1d9d68fd 100644
--- a/api/booleans.yaml
+++ b/api/booleans.yaml
@@ -13,6 +13,12 @@ Bool.parse:
       type: 'Text'
       description: >
         The string containing the boolean value.
+    remainder:
+      type: '&Text?'
+      default: 'none'
+      description: >
+        If non-none, this argument will be set to the remainder of the text after the matching part.
+        If none, parsing will only succeed if the entire text matches.
   example: |
     >> Bool.parse("yes")
     = yes : Bool?
@@ -20,4 +26,11 @@ Bool.parse:
     = no : Bool?
     >> Bool.parse("???")
     = none : Bool?
-    
+
+    >> Bool.parse("yesJUNK")
+    = none : Bool?
+    remainder : Text
+    >> Bool.parse("yesJUNK", &remainder)
+    = yes : Bool?
+    >> remainder
+    = "JUNK"
diff --git a/api/bytes.md b/api/bytes.md
index 908d78e2..fe8dddb1 100644
--- a/api/bytes.md
+++ b/api/bytes.md
@@ -86,7 +86,7 @@ high | `Byte` | The upper bound to check (inclusive).  | -
 ## Byte.parse
 
 ```tomo
-Byte.parse : func(text: Text -> Byte?)
+Byte.parse : func(text: Text, remainder: &Text? = none -> Byte?)
 ```
 
 Parse a byte literal from text.
@@ -94,6 +94,7 @@ Parse a byte literal from text.
 Argument | Type | Description | Default
 ---------|------|-------------|---------
 text | `Text` | The text to parse.  | -
+remainder | `&Text?` | If non-none, this argument will be set to the remainder of the text after the matching part. If none, parsing will only succeed if the entire text matches.  | `none`
 
 **Return:** The byte parsed from the text, if successful, otherwise `none`.
 
@@ -101,9 +102,17 @@ text | `Text` | The text to parse.  | -
 **Example:**
 ```tomo
 >> Byte.parse("5")
-= Byte(5)?
+= Byte(5) : Byte?
 >> Byte.parse("asdf")
-= none
+= none : Byte?
+
+>> Byte.parse("123xyz")
+= none : Byte?
+remainder : Text
+>> Byte.parse("123xyz", &remainder)
+= Byte(123) : Byte?
+>> remainder
+= "xyz"
 
 ```
 ## Byte.to
diff --git a/api/bytes.yaml b/api/bytes.yaml
index 2785513d..f7b8cb5d 100644
--- a/api/bytes.yaml
+++ b/api/bytes.yaml
@@ -54,7 +54,7 @@ Byte.hex:
   example: |
     >> Byte(18).hex()
     = "0x12"
-    
+
 Byte.is_between:
   short: test if inside a range
   description: >
@@ -83,7 +83,7 @@ Byte.is_between:
     = no
     >> Byte(7).is_between(1, 7)
     = yes
-    
+
 Byte.parse:
   short: convert text to a byte
   description: >
@@ -97,12 +97,26 @@ Byte.parse:
       type: 'Text'
       description: >
         The text to parse.
+    remainder:
+      type: '&Text?'
+      default: 'none'
+      description: >
+        If non-none, this argument will be set to the remainder of the text after the matching part.
+        If none, parsing will only succeed if the entire text matches.
   example: |
     >> Byte.parse("5")
-    = Byte(5)?
+    = Byte(5) : Byte?
     >> Byte.parse("asdf")
-    = none
-    
+    = none : Byte?
+
+    >> Byte.parse("123xyz")
+    = none : Byte?
+    remainder : Text
+    >> Byte.parse("123xyz", &remainder)
+    = Byte(123) : Byte?
+    >> remainder
+    = "xyz"
+
 Byte.to:
   short: iterate over a range of bytes
   description: >
@@ -132,7 +146,7 @@ Byte.to:
     = [Byte(2), Byte(3), Byte(4), Byte(5)]
     >> [x for x in Byte(5).to(2)]
     = [Byte(5), Byte(4), Byte(3), Byte(2)]
-    
+
     >> [x for x in Byte(2).to(5, step=2)]
     = [Byte(2), Byte(4)]
-    
+
diff --git a/api/integers.md b/api/integers.md
index efb891bf..6468589e 100644
--- a/api/integers.md
+++ b/api/integers.md
@@ -272,7 +272,7 @@ stop if i == 10
 ## Int.parse
 
 ```tomo
-Int.parse : func(text: Text -> Int?)
+Int.parse : func(text: Text, remainder: &Text? = none -> Int?)
 ```
 
 Converts a text representation of an integer into an integer.
@@ -280,6 +280,7 @@ Converts a text representation of an integer into an integer.
 Argument | Type | Description | Default
 ---------|------|-------------|---------
 text | `Text` | The text containing the integer.  | -
+remainder | `&Text?` | If non-none, this argument will be set to the remainder of the text after the matching part. If none, parsing will only succeed if the entire text matches.  | `none`
 
 **Return:** The integer represented by the text. If the given text contains a value outside of the representable range or if the entire text can't be parsed as an integer, `none` will be returned.
 
@@ -291,6 +292,14 @@ text | `Text` | The text containing the integer.  | -
 >> Int.parse("0xFF")
 = 255 : Int?
 
+>> Int.parse("123xyz")
+= none
+remainder : Text
+>> Int.parse("123xyz", &remainder)
+= 123 : Int?
+>> remainder
+= "xyz"
+
 # Can't parse:
 >> Int.parse("asdf")
 = none : Int?
diff --git a/api/integers.yaml b/api/integers.yaml
index a91a21ce..4d7e423f 100644
--- a/api/integers.yaml
+++ b/api/integers.yaml
@@ -14,7 +14,7 @@ Int.abs:
   example: |
     >> (-10).abs()
     = 10
-    
+
 Int.choose:
   short: binomial coefficient
   description: >
@@ -38,7 +38,7 @@ Int.choose:
   example: |
     >> (4).choose(2)
     = 6
-    
+
 Int.clamped:
   short: clamp an integer
   description: >
@@ -64,7 +64,7 @@ Int.clamped:
   example: |
     >> (2).clamped(5, 10)
     = 5
-    
+
 Int.factorial:
   short: factorial
   description: >
@@ -147,7 +147,7 @@ Int.hex:
   example: |
     >> (255).hex(digits=4, uppercase=yes, prefix=yes)
     = "0x00FF"
-    
+
 Int.is_between:
   short: test if an int is in a range
   description: >
@@ -176,7 +176,7 @@ Int.is_between:
     = no
     >> (7).is_between(1, 7)
     = yes
-    
+
 Int.is_prime:
   short: check if an integer is prime
   description: >
@@ -205,7 +205,7 @@ Int.is_prime:
     = yes
     >> (6).is_prime()
     = no
-    
+
 Int.next_prime:
   short: get the next prime
   description: >
@@ -227,7 +227,7 @@ Int.next_prime:
   example: |
     >> (11).next_prime()
     = 13
-    
+
 Int.octal:
   short: convert to octal
   description: >
@@ -254,7 +254,7 @@ Int.octal:
   example: |
     >> (64).octal(digits=4, prefix=yes)
     = "0o0100"
-    
+
 Int.onward:
   short: iterate from a number onward
   description: >
@@ -281,7 +281,7 @@ Int.onward:
     stop if i == 10
     >> nums[]
     = [5, 6, 7, 8, 9, 10]
-    
+
 Int.parse:
   short: convert text to integer
   description: >
@@ -297,20 +297,34 @@ Int.parse:
       type: 'Text'
       description: >
         The text containing the integer.
+    remainder:
+      type: '&Text?'
+      default: 'none'
+      description: >
+        If non-none, this argument will be set to the remainder of the text after the matching part.
+        If none, parsing will only succeed if the entire text matches.
   example: |
     >> Int.parse("123")
     = 123 : Int?
     >> Int.parse("0xFF")
     = 255 : Int?
-    
+
+    >> Int.parse("123xyz")
+    = none
+    remainder : Text
+    >> Int.parse("123xyz", &remainder)
+    = 123 : Int?
+    >> remainder
+    = "xyz"
+
     # Can't parse:
     >> Int.parse("asdf")
     = none : Int?
-    
+
     # Outside valid range:
     >> Int8.parse("9999999")
     = none : Int8?
-    
+
 Int.prev_prime:
   short: get the previous prime
   description: >
@@ -334,7 +348,7 @@ Int.prev_prime:
   example: |
     >> (11).prev_prime()
     = 7
-    
+
 Int.sqrt:
   short: square root
   description: >
@@ -353,7 +367,7 @@ Int.sqrt:
     = 4
     >> (17).sqrt()
     = 4
-    
+
 Int.to:
   short: iterate a range of integers
   description: >
@@ -383,7 +397,7 @@ Int.to:
     = [2, 3, 4, 5]
     >> [x for x in (5).to(2)]
     = [5, 4, 3, 2]
-    
+
     >> [x for x in (2).to(5, step=2)]
     = [2, 4]
-    
+
diff --git a/api/nums.md b/api/nums.md
index 471a7739..ef771171 100644
--- a/api/nums.md
+++ b/api/nums.md
@@ -885,7 +885,7 @@ y | `Num` | The direction towards which to find the next representable value.  |
 ## Num.parse
 
 ```tomo
-Num.parse : func(text: Text -> Num?)
+Num.parse : func(text: Text, remainder: &Text? = none -> Num?)
 ```
 
 Converts a text representation of a number into a floating-point number.
@@ -893,6 +893,7 @@ Converts a text representation of a number into a floating-point number.
 Argument | Type | Description | Default
 ---------|------|-------------|---------
 text | `Text` | The text containing the number.  | -
+remainder | `&Text?` | If non-none, this argument will be set to the remainder of the text after the matching part. If none, parsing will only succeed if the entire text matches.  | `none`
 
 **Return:** The number represented by the text or `none` if the entire text can't be parsed as a number.
 
@@ -900,9 +901,17 @@ text | `Text` | The text containing the number.  | -
 **Example:**
 ```tomo
 >> Num.parse("3.14")
-= 3.14
+= 3.14 : Num?
 >> Num.parse("1e3")
-= 1000
+= 1000 : Num?
+
+>> Num.parse("1.5junk")
+= none : Num?
+remainder : Text
+>> Num.parse("1.5junk", &remainder)
+= 1.5 : Num?
+>> remainder
+= "junk"
 
 ```
 ## Num.percent
diff --git a/api/nums.yaml b/api/nums.yaml
index e666a0d6..2c18fac5 100644
--- a/api/nums.yaml
+++ b/api/nums.yaml
@@ -686,11 +686,25 @@ Num.parse:
       type: 'Text'
       description: >
         The text containing the number.
+    remainder:
+      type: '&Text?'
+      default: 'none'
+      description: >
+        If non-none, this argument will be set to the remainder of the text after the matching part.
+        If none, parsing will only succeed if the entire text matches.
   example: |
     >> Num.parse("3.14")
-    = 3.14
+    = 3.14 : Num?
     >> Num.parse("1e3")
-    = 1000
+    = 1000 : Num?
+
+    >> Num.parse("1.5junk")
+    = none : Num?
+    remainder : Text
+    >> Num.parse("1.5junk", &remainder)
+    = 1.5 : Num?
+    >> remainder
+    = "junk"
     
 Num.percent:
   short: format as a percentage
diff --git a/api/text.md b/api/text.md
index e500e7bf..bdff6841 100644
--- a/api/text.md
+++ b/api/text.md
@@ -202,7 +202,7 @@ text | `Text` | The text from which to extract codepoint names.  | -
 ## Text.ends_with
 
 ```tomo
-Text.ends_with : func(text: Text, suffix: Text -> Bool)
+Text.ends_with : func(text: Text, suffix: Text, remainder: &Text? = none -> Bool)
 ```
 
 Checks if the `Text` ends with a literal suffix text.
@@ -211,6 +211,7 @@ Argument | Type | Description | Default
 ---------|------|-------------|---------
 text | `Text` | The text to be searched.  | -
 suffix | `Text` | The literal suffix text to check for.  | -
+remainder | `&Text?` | If non-none, this value will be set to the rest of the text up to the trailing suffix. If the suffix is not found, this value will be set to the original text.  | `none`
 
 **Return:** `yes` if the text has the target, `no` otherwise.
 
@@ -219,6 +220,11 @@ suffix | `Text` | The literal suffix text to check for.  | -
 ```tomo
 >> "hello world".ends_with("world")
 = yes
+remainder : Text
+>> "hello world".ends_with("world", &remainder)
+= yes
+>> remainder
+= "hello "
 
 ```
 ## Text.from
@@ -696,7 +702,7 @@ delimiters | `Text` | A text containing delimiters to use for splitting the text
 ## Text.starts_with
 
 ```tomo
-Text.starts_with : func(text: Text, prefix: Text -> Bool)
+Text.starts_with : func(text: Text, prefix: Text, remainder: &Text? = none -> Bool)
 ```
 
 Checks if the `Text` starts with a literal prefix text.
@@ -705,6 +711,7 @@ Argument | Type | Description | Default
 ---------|------|-------------|---------
 text | `Text` | The text to be searched.  | -
 prefix | `Text` | The literal prefix text to check for.  | -
+remainder | `&Text?` | If non-none, this value will be set to the rest of the text after the prefix. If the prefix is not found, this value will be set to the original text.  | `none`
 
 **Return:** `yes` if the text has the given prefix, `no` otherwise.
 
@@ -713,6 +720,11 @@ prefix | `Text` | The literal prefix text to check for.  | -
 ```tomo
 >> "hello world".starts_with("hello")
 = yes
+remainder : Text
+>> "hello world".starts_with("hello", &remainder)
+= yes
+>> remainder
+= " world"
 
 ```
 ## Text.title
diff --git a/api/text.yaml b/api/text.yaml
index eb9dc286..c8d70f0b 100644
--- a/api/text.yaml
+++ b/api/text.yaml
@@ -14,7 +14,7 @@ Text.as_c_string:
   example: |
     >> "Hello".as_c_string()
     = CString("Hello")
-    
+
 Text.at:
   short: get a letter
   description: >
@@ -39,7 +39,7 @@ Text.at:
   example: |
     >> "Amélie".at(3)
     = "é"
-    
+
 Text.by_line:
   short: iterate by line
   description: >
@@ -66,7 +66,7 @@ Text.by_line:
     for line in text.by_line()
     # Prints: "line one" then "line two":
     say(line)
-    
+
 Text.by_split:
   short: iterate by a spliting text
   description: >
@@ -97,7 +97,7 @@ Text.by_split:
     for chunk in text.by_split(",")
     # Prints: "one" then "two" then "three":
     say(chunk)
-    
+
 Text.by_split_any:
   short: iterate by one of many splitting characters
   description: >
@@ -128,7 +128,7 @@ Text.by_split_any:
     for chunk in text.by_split_any(",;")
     # Prints: "one" then "two" then "three":
     say(chunk)
-    
+
 Text.bytes:
   short: get UTF8 bytes
   description: >
@@ -146,7 +146,7 @@ Text.bytes:
   example: |
     >> "Amélie".bytes()
     = [65, 109, 195, 169, 108, 105, 101]
-    
+
 Text.caseless_equals:
   short: case-insensitive comparison
   description: >
@@ -173,11 +173,11 @@ Text.caseless_equals:
   example: |
     >> "A".caseless_equals("a")
     = yes
-    
+
     # Turkish lowercase "I" is "ı" (dotless I), not "i"
     >> "I".caseless_equals("i", language="tr_TR")
     = no
-    
+
 Text.codepoint_names:
   short: get unicode codepoint names
   description: >
@@ -194,7 +194,7 @@ Text.codepoint_names:
   example: |
     >> "Amélie".codepoint_names()
     = ["LATIN CAPITAL LETTER A", "LATIN SMALL LETTER M", "LATIN SMALL LETTER E WITH ACUTE", "LATIN SMALL LETTER L", "LATIN SMALL LETTER I", "LATIN SMALL LETTER E"]
-    
+
 Text.ends_with:
   short: check suffix
   description: >
@@ -212,10 +212,21 @@ Text.ends_with:
       type: 'Text'
       description: >
         The literal suffix text to check for.
+    remainder:
+      type: '&Text?'
+      default: 'none'
+      description: >
+        If non-none, this value will be set to the rest of the text up to the trailing suffix.
+        If the suffix is not found, this value will be set to the original text.
   example: |
     >> "hello world".ends_with("world")
     = yes
-    
+    remainder : Text
+    >> "hello world".ends_with("world", &remainder)
+    = yes
+    >> remainder
+    = "hello "
+
 Text.from:
   short: slice from a starting index
   description: >
@@ -240,10 +251,10 @@ Text.from:
   example: |
     >> "hello".from(2)
     = "ello"
-    
+
     >> "hello".from(-2)
     = "lo"
-    
+
 Text.from_bytes:
   short: convert UTF8 byte list to text
   description: >
@@ -263,7 +274,7 @@ Text.from_bytes:
   example: |
     >> Text.from_bytes([195, 133, 107, 101])
     = "Åke"
-    
+
 Text.from_c_string:
   short: convert C-style string to text
   description: >
@@ -280,7 +291,7 @@ Text.from_c_string:
   example: |
     >> Text.from_c_string(CString("Hello"))
     = "Hello"
-    
+
 Text.from_codepoint_names:
   short: convert list of unicode codepoint names to text
   description: >
@@ -306,7 +317,7 @@ Text.from_codepoint_names:
     "LATIN SMALL LETTER E",
     ]
     = "Åke"
-    
+
 Text.from_codepoints:
   short: convert UTF32 codepoints to text
   description: >
@@ -326,7 +337,7 @@ Text.from_codepoints:
   example: |
     >> Text.from_codepoints([197, 107, 101])
     = "Åke"
-    
+
 Text.has:
   short: check for substring
   description: >
@@ -349,7 +360,7 @@ Text.has:
     = yes
     >> "hello world".has("xxx")
     = no
-    
+
 Text.join:
   short: concatenate with separator
   description: >
@@ -370,7 +381,7 @@ Text.join:
   example: |
     >> ", ".join(["one", "two", "three"])
     = "one, two, three"
-    
+
 Text.middle_pad:
   short: pad text, centered
   description: >
@@ -405,7 +416,7 @@ Text.middle_pad:
     = "  x   "
     >> "x".middle_pad(10, "ABC")
     = "ABCAxABCAB"
-    
+
 Text.left_pad:
   short: left-pad text
   description: >
@@ -440,7 +451,7 @@ Text.left_pad:
     = "    x"
     >> "x".left_pad(5, "ABC")
     = "ABCAx"
-    
+
 Text.lines:
   short: get list of lines
   description: >
@@ -466,7 +477,7 @@ Text.lines:
     = ["one", "two", "three"]
     >> "".lines()
     = []
-    
+
 Text.lower:
   short: convert to lowercase
   description: >
@@ -488,10 +499,10 @@ Text.lower:
   example: |
     >> "AMÉLIE".lower()
     = "amélie"
-    
+
     >> "I".lower(language="tr_TR")
     >> "ı"
-    
+
 Text.quoted:
   short: add quotation marks and escapes
   description: >
@@ -518,7 +529,7 @@ Text.quoted:
   example: |
     >> "one\ntwo".quoted()
     = "\"one\\ntwo\""
-    
+
 Text.repeat:
   short: repeat text
   description: >
@@ -539,7 +550,7 @@ Text.repeat:
   example: |
     >> "Abc".repeat(3)
     = "AbcAbcAbc"
-    
+
 Text.replace:
   short: replace a substring
   description: >
@@ -564,7 +575,7 @@ Text.replace:
   example: |
     >> "Hello world".replace("world", "there")
     = "Hello there"
-    
+
 Text.reversed:
   short: get a reversed copy
   description: >
@@ -581,7 +592,7 @@ Text.reversed:
   example: |
     >> "Abc".reversed()
     = "cbA"
-    
+
 Text.right_pad:
   short: right-pad text
   description: >
@@ -616,7 +627,7 @@ Text.right_pad:
     = "x    "
     >> "x".right_pad(5, "ABC")
     = "xABCA"
-    
+
 Text.slice:
   short: get a slice of a text
   description: >
@@ -647,13 +658,13 @@ Text.slice:
   example: |
     >> "hello".slice(2, 3)
     = "el"
-    
+
     >> "hello".slice(to=-2)
     = "hell"
-    
+
     >> "hello".slice(from=2)
     = "ello"
-    
+
 Text.split:
   short: split a text by a delimiter
   description: >
@@ -681,10 +692,10 @@ Text.split:
   example: |
     >> "one,two,,three".split(",")
     = ["one", "two", "", "three"]
-    
+
     >> "abc".split()
     = ["a", "b", "c"]
-    
+
 Text.split_any:
   short: split a text by multiple delimiters
   description: >
@@ -712,7 +723,7 @@ Text.split_any:
   example: |
     >> "one, two,,three".split_any(", ")
     = ["one", "two", "three"]
-    
+
 Text.starts_with:
   short: check prefix
   description: >
@@ -730,10 +741,21 @@ Text.starts_with:
       type: 'Text'
       description: >
         The literal prefix text to check for.
+    remainder:
+      type: '&Text?'
+      default: 'none'
+      description: >
+        If non-none, this value will be set to the rest of the text after the prefix.
+        If the prefix is not found, this value will be set to the original text.
   example: |
     >> "hello world".starts_with("hello")
     = yes
-    
+    remainder : Text
+    >> "hello world".starts_with("hello", &remainder)
+    = yes
+    >> remainder
+    = " world"
+
 Text.title:
   short: titlecase
   description: >
@@ -755,11 +777,11 @@ Text.title:
   example: |
     >> "amélie".title()
     = "Amélie"
-    
+
     # In Turkish, uppercase "i" is "İ"
     >> "i".title(language="tr_TR")
     = "İ"
-    
+
 Text.to:
   short: slice to an end index
   description: >
@@ -784,10 +806,10 @@ Text.to:
   example: |
     >> "goodbye".to(3)
     = "goo"
-    
+
     >> "goodbye".to(-2)
     = "goodby"
-    
+
 Text.translate:
   short: perform multiple replacements
   description: >
@@ -819,7 +841,7 @@ Text.translate:
         "'" = "'",
     })
     = "A <tag> & an ampersand"
-    
+
 Text.trim:
   short: trim characters
   description: >
@@ -851,13 +873,13 @@ Text.trim:
   example: |
     >> "   x y z    \n".trim()
     = "x y z"
-    
+
     >> "one,".trim(",")
     = "one"
-    
+
     >> "   xyz   ".trim(right=no)
     = "xyz   "
-    
+
 Text.upper:
   short: uppercase
   description: >
@@ -879,11 +901,11 @@ Text.upper:
   example: |
     >> "amélie".upper()
     = "AMÉLIE"
-    
+
     # In Turkish, uppercase "i" is "İ"
     >> "i".upper(language="tr_TR")
     = "İ"
-    
+
 Text.utf32_codepoints:
   short: get UTF32 codepoints
   description: >
@@ -900,7 +922,7 @@ Text.utf32_codepoints:
   example: |
     >> "Amélie".utf32_codepoints()
     = [65, 109, 233, 108, 105, 101]
-    
+
 Text.width:
   short: get display width
   description: >
@@ -924,7 +946,7 @@ Text.width:
     = 6
     >> "🤠".width()
     = 2
-    
+
 Text.without_prefix:
   short: remove prefix
   description: >
@@ -948,7 +970,7 @@ Text.without_prefix:
     = "baz"
     >> "qux".without_prefix("foo:")
     = "qux"
-    
+
 Text.without_suffix:
   short: remove suffix
   description: >
@@ -972,4 +994,4 @@ Text.without_suffix:
     = "baz"
     >> "qux".without_suffix(".foo")
     = "qux"
-    
+
diff --git a/lib/patterns/CHANGES.md b/lib/patterns/CHANGES.md
index 42ae752c..cf6254cb 100644
--- a/lib/patterns/CHANGES.md
+++ b/lib/patterns/CHANGES.md
@@ -1,5 +1,8 @@
 # Version History
 
+## v1.1
+- Added `Text.matching_pattern(text:Text, pattern:Pattern, pos:Int = 1 -> PatternMatch?)`
+
 ## v1.0
 
 Initial version
diff --git a/lib/patterns/patterns.c b/lib/patterns/patterns.c
index 74d542b8..224a00a0 100644
--- a/lib/patterns/patterns.c
+++ b/lib/patterns/patterns.c
@@ -663,6 +663,8 @@ static pat_t parse_next_pat(TextIter_t *state, int64_t *index)
         case 'w':
             if (strcasecmp(prop_name, "word") == 0) {
                 return PAT(PAT_FUNCTION, .fn=match_id);
+            } else if (strcasecmp(prop_name, "ws") == 0 || strcasecmp(prop_name, "whitespace") == 0) {
+                return PAT(PAT_PROPERTY, .property=UC_PROPERTY_WHITE_SPACE);
             }
             break;
         default: break;
@@ -837,10 +839,10 @@ static OptionalPatternMatch find(Text_t text, Text_t pattern, Int_t from_index)
 
 PUREFUNC static bool Pattern$has(Text_t text, Text_t pattern)
 {
-    if (Text$starts_with(pattern, Text("{start}"))) {
+    if (Text$starts_with(pattern, Text("{start}"), &pattern)) {
         int64_t m = match(text, 0, pattern, 0, NULL, 0);
         return m >= 0;
-    } else if (Text$ends_with(text, Text("{end}"))) {
+    } else if (Text$ends_with(text, Text("{end}"), NULL)) {
         for (int64_t i = text.length-1; i >= 0; i--) {
             int64_t match_len = match(text, i, pattern, 0, NULL, 0);
             if (match_len >= 0 && i + match_len == text.length)
@@ -860,6 +862,25 @@ static bool Pattern$matches(Text_t text, Text_t pattern)
     return (match_len == text.length);
 }
 
+static bool Pattern$match_at(Text_t text, Text_t pattern, Int_t pos, PatternMatch *dest)
+{
+    int64_t start = Int64$from_int(pos, false) - 1;
+    capture_t captures[MAX_BACKREFS] = {};
+    int64_t match_len = match(text, start, pattern, 0, captures, 0);
+    if (match_len < 0)
+        return false;
+
+    List_t capture_list = {};
+    for (int i = 0; captures[i].occupied; i++) {
+        Text_t capture = Text$slice(text, I(captures[i].index+1), I(captures[i].index+captures[i].length));
+        List$insert(&capture_list, &capture, I(0), sizeof(Text_t));
+    }
+    dest->text = Text$slice(text, I(start+1), I(start+match_len));
+    dest->index = I(start+1);
+    dest->captures = capture_list;
+    return true;
+}
+
 static OptionalList_t Pattern$captures(Text_t text, Text_t pattern)
 {
     capture_t captures[MAX_BACKREFS] = {};
diff --git a/lib/patterns/patterns.tm b/lib/patterns/patterns.tm
index bab0c3dc..c5444b86 100644
--- a/lib/patterns/patterns.tm
+++ b/lib/patterns/patterns.tm
@@ -10,6 +10,12 @@ lang Pat
         return Pat.from_text("$n")
 
 extend Text
+    func matching_pattern(text:Text, pattern:Pat, pos:Int = 1 -> PatternMatch?)
+        result : PatternMatch
+        if C_code:Bool(Pattern$match_at(@text, @pattern, @pos, (void*)&@result))
+            return result
+        return none
+
     func matches_pattern(text:Text, pattern:Pat -> Bool)
         return C_code:Bool(Pattern$matches(@text, @pattern))
 
@@ -45,3 +51,16 @@ extend Text
 
     func trim_pattern(text:Text, pattern=$Pat"{space}", left=yes, right=yes -> Text)
         return C_code:Text(Pattern$trim(@text, @pattern, @left, @right))
+
+func main()
+    >> "Hello world".matching_pattern($Pat'{id}')
+    >> "...Hello world".matching_pattern($Pat'{id}')
+# func main(pattern:Pat, input=(/dev/stdin))
+#     for line in input.by_line()!
+#         skip if not line.has_pattern(pattern)
+#         pos := 1
+#         for match in line.by_pattern(pattern)
+#             say(line.slice(pos, match.index-1), newline=no)
+#             say("\033[34;1m$(match.text)\033[m", newline=no)
+#             pos = match.index + match.text.length
+#         say(line.from(pos), newline=yes)
diff --git a/man/man3/tomo-Bool.parse.3 b/man/man3/tomo-Bool.parse.3
index 81830fb3..e1d5f3b7 100644
--- a/man/man3/tomo-Bool.parse.3
+++ b/man/man3/tomo-Bool.parse.3
@@ -2,14 +2,14 @@
 .\" Copyright (c) 2025 Bruce Hill
 .\" All rights reserved.
 .\"
-.TH Bool.parse 3 2025-04-30 "Tomo man-pages"
+.TH Bool.parse 3 2025-08-16 "Tomo man-pages"
 .SH NAME
 Bool.parse \- parse into boolean
 .SH LIBRARY
 Tomo Standard Library
 .SH SYNOPSIS
 .nf
-.BI Bool.parse\ :\ func(text:\ Text\ ->\ Bool?)
+.BI Bool.parse\ :\ func(text:\ Text,\ remainder:\ &Text?\ =\ none\ ->\ Bool?)
 .fi
 .SH DESCRIPTION
 Converts a text representation of a boolean value into a boolean. Acceptable boolean values are case-insensitive variations of `yes`/`no`, `y`/`n`, `true`/`false`, `on`/`off`.
@@ -23,6 +23,7 @@ lb lb lbx lb
 l l l l.
 Name	Type	Description	Default
 text	Text	The string containing the boolean value. 	-
+remainder	&Text?	If non-none, this argument will be set to the remainder of the text after the matching part. If none, parsing will only succeed if the entire text matches. 	none
 .TE
 .SH RETURN
 `yes` if the string matches a recognized truthy boolean value; otherwise return `no`.
@@ -35,4 +36,12 @@ text	Text	The string containing the boolean value. 	-
 = no : Bool?
 >> Bool.parse("???")
 = none : Bool?
+
+>> Bool.parse("yesJUNK")
+= none : Bool?
+remainder : Text
+>> Bool.parse("yesJUNK", &remainder)
+= yes : Bool?
+>> remainder
+= "JUNK"
 .EE
diff --git a/man/man3/tomo-Byte.parse.3 b/man/man3/tomo-Byte.parse.3
index 6e4d3bb6..1beeb3a4 100644
--- a/man/man3/tomo-Byte.parse.3
+++ b/man/man3/tomo-Byte.parse.3
@@ -2,14 +2,14 @@
 .\" Copyright (c) 2025 Bruce Hill
 .\" All rights reserved.
 .\"
-.TH Byte.parse 3 2025-04-30 "Tomo man-pages"
+.TH Byte.parse 3 2025-08-16 "Tomo man-pages"
 .SH NAME
 Byte.parse \- convert text to a byte
 .SH LIBRARY
 Tomo Standard Library
 .SH SYNOPSIS
 .nf
-.BI Byte.parse\ :\ func(text:\ Text\ ->\ Byte?)
+.BI Byte.parse\ :\ func(text:\ Text,\ remainder:\ &Text?\ =\ none\ ->\ Byte?)
 .fi
 .SH DESCRIPTION
 Parse a byte literal from text.
@@ -23,6 +23,7 @@ lb lb lbx lb
 l l l l.
 Name	Type	Description	Default
 text	Text	The text to parse. 	-
+remainder	&Text?	If non-none, this argument will be set to the remainder of the text after the matching part. If none, parsing will only succeed if the entire text matches. 	none
 .TE
 .SH RETURN
 The byte parsed from the text, if successful, otherwise `none`.
@@ -30,7 +31,15 @@ The byte parsed from the text, if successful, otherwise `none`.
 .SH EXAMPLES
 .EX
 >> Byte.parse("5")
-= Byte(5)?
+= Byte(5) : Byte?
 >> Byte.parse("asdf")
-= none
+= none : Byte?
+
+>> Byte.parse("123xyz")
+= none : Byte?
+remainder : Text
+>> Byte.parse("123xyz", &remainder)
+= Byte(123) : Byte?
+>> remainder
+= "xyz"
 .EE
diff --git a/man/man3/tomo-Int.parse.3 b/man/man3/tomo-Int.parse.3
index 8facec2a..07a00e85 100644
--- a/man/man3/tomo-Int.parse.3
+++ b/man/man3/tomo-Int.parse.3
@@ -2,14 +2,14 @@
 .\" Copyright (c) 2025 Bruce Hill
 .\" All rights reserved.
 .\"
-.TH Int.parse 3 2025-04-30 "Tomo man-pages"
+.TH Int.parse 3 2025-08-16 "Tomo man-pages"
 .SH NAME
 Int.parse \- convert text to integer
 .SH LIBRARY
 Tomo Standard Library
 .SH SYNOPSIS
 .nf
-.BI Int.parse\ :\ func(text:\ Text\ ->\ Int?)
+.BI Int.parse\ :\ func(text:\ Text,\ remainder:\ &Text?\ =\ none\ ->\ Int?)
 .fi
 .SH DESCRIPTION
 Converts a text representation of an integer into an integer.
@@ -23,6 +23,7 @@ lb lb lbx lb
 l l l l.
 Name	Type	Description	Default
 text	Text	The text containing the integer. 	-
+remainder	&Text?	If non-none, this argument will be set to the remainder of the text after the matching part. If none, parsing will only succeed if the entire text matches. 	none
 .TE
 .SH RETURN
 The integer represented by the text. If the given text contains a value outside of the representable range or if the entire text can't be parsed as an integer, `none` will be returned.
@@ -34,6 +35,14 @@ The integer represented by the text. If the given text contains a value outside
 >> Int.parse("0xFF")
 = 255 : Int?
 
+>> Int.parse("123xyz")
+= none
+remainder : Text
+>> Int.parse("123xyz", &remainder)
+= 123 : Int?
+>> remainder
+= "xyz"
+
 # Can't parse:
 >> Int.parse("asdf")
 = none : Int?
diff --git a/man/man3/tomo-Num.parse.3 b/man/man3/tomo-Num.parse.3
index 48ab90c8..63165e59 100644
--- a/man/man3/tomo-Num.parse.3
+++ b/man/man3/tomo-Num.parse.3
@@ -2,14 +2,14 @@
 .\" Copyright (c) 2025 Bruce Hill
 .\" All rights reserved.
 .\"
-.TH Num.parse 3 2025-04-30 "Tomo man-pages"
+.TH Num.parse 3 2025-08-16 "Tomo man-pages"
 .SH NAME
 Num.parse \- convert text to number
 .SH LIBRARY
 Tomo Standard Library
 .SH SYNOPSIS
 .nf
-.BI Num.parse\ :\ func(text:\ Text\ ->\ Num?)
+.BI Num.parse\ :\ func(text:\ Text,\ remainder:\ &Text?\ =\ none\ ->\ Num?)
 .fi
 .SH DESCRIPTION
 Converts a text representation of a number into a floating-point number.
@@ -23,6 +23,7 @@ lb lb lbx lb
 l l l l.
 Name	Type	Description	Default
 text	Text	The text containing the number. 	-
+remainder	&Text?	If non-none, this argument will be set to the remainder of the text after the matching part. If none, parsing will only succeed if the entire text matches. 	none
 .TE
 .SH RETURN
 The number represented by the text or `none` if the entire text can't be parsed as a number.
@@ -30,7 +31,15 @@ The number represented by the text or `none` if the entire text can't be parsed
 .SH EXAMPLES
 .EX
 >> Num.parse("3.14")
-= 3.14
+= 3.14 : Num?
 >> Num.parse("1e3")
-= 1000
+= 1000 : Num?
+
+>> Num.parse("1.5junk")
+= none : Num?
+remainder : Text
+>> Num.parse("1.5junk", &remainder)
+= 1.5 : Num?
+>> remainder
+= "junk"
 .EE
diff --git a/man/man3/tomo-Text.ends_with.3 b/man/man3/tomo-Text.ends_with.3
index 7d19109b..38fa4c0b 100644
--- a/man/man3/tomo-Text.ends_with.3
+++ b/man/man3/tomo-Text.ends_with.3
@@ -2,14 +2,14 @@
 .\" Copyright (c) 2025 Bruce Hill
 .\" All rights reserved.
 .\"
-.TH Text.ends_with 3 2025-04-30 "Tomo man-pages"
+.TH Text.ends_with 3 2025-08-16 "Tomo man-pages"
 .SH NAME
 Text.ends_with \- check suffix
 .SH LIBRARY
 Tomo Standard Library
 .SH SYNOPSIS
 .nf
-.BI Text.ends_with\ :\ func(text:\ Text,\ suffix:\ Text\ ->\ Bool)
+.BI Text.ends_with\ :\ func(text:\ Text,\ suffix:\ Text,\ remainder:\ &Text?\ =\ none\ ->\ Bool)
 .fi
 .SH DESCRIPTION
 Checks if the `Text` ends with a literal suffix text.
@@ -24,6 +24,7 @@ l l l l.
 Name	Type	Description	Default
 text	Text	The text to be searched. 	-
 suffix	Text	The literal suffix text to check for. 	-
+remainder	&Text?	If non-none, this value will be set to the rest of the text up to the trailing suffix. If the suffix is not found, this value will be set to the original text. 	none
 .TE
 .SH RETURN
 `yes` if the text has the target, `no` otherwise.
@@ -32,4 +33,9 @@ suffix	Text	The literal suffix text to check for. 	-
 .EX
 >> "hello world".ends_with("world")
 = yes
+remainder : Text
+>> "hello world".ends_with("world", &remainder)
+= yes
+>> remainder
+= "hello "
 .EE
diff --git a/man/man3/tomo-Text.starts_with.3 b/man/man3/tomo-Text.starts_with.3
index 0894ec74..fafa2a55 100644
--- a/man/man3/tomo-Text.starts_with.3
+++ b/man/man3/tomo-Text.starts_with.3
@@ -2,14 +2,14 @@
 .\" Copyright (c) 2025 Bruce Hill
 .\" All rights reserved.
 .\"
-.TH Text.starts_with 3 2025-04-30 "Tomo man-pages"
+.TH Text.starts_with 3 2025-08-16 "Tomo man-pages"
 .SH NAME
 Text.starts_with \- check prefix
 .SH LIBRARY
 Tomo Standard Library
 .SH SYNOPSIS
 .nf
-.BI Text.starts_with\ :\ func(text:\ Text,\ prefix:\ Text\ ->\ Bool)
+.BI Text.starts_with\ :\ func(text:\ Text,\ prefix:\ Text,\ remainder:\ &Text?\ =\ none\ ->\ Bool)
 .fi
 .SH DESCRIPTION
 Checks if the `Text` starts with a literal prefix text.
@@ -24,6 +24,7 @@ l l l l.
 Name	Type	Description	Default
 text	Text	The text to be searched. 	-
 prefix	Text	The literal prefix text to check for. 	-
+remainder	&Text?	If non-none, this value will be set to the rest of the text after the prefix. If the prefix is not found, this value will be set to the original text. 	none
 .TE
 .SH RETURN
 `yes` if the text has the given prefix, `no` otherwise.
@@ -32,4 +33,9 @@ prefix	Text	The literal prefix text to check for. 	-
 .EX
 >> "hello world".starts_with("hello")
 = yes
+remainder : Text
+>> "hello world".starts_with("hello", &remainder)
+= yes
+>> remainder
+= " world"
 .EE
diff --git a/src/compile.c b/src/compile.c
index 1795bb38..eb250d74 100644
--- a/src/compile.c
+++ b/src/compile.c
@@ -1513,7 +1513,7 @@ static Text_t _compile_statement(env_t *env, ast_t *ast)
             struct { const char *name; binding_t *b; } *entry = closed_vars.entries.data + closed_vars.entries.stride*i;
             if (entry->b->type->tag == ModuleType)
                 continue;
-            if (Text$starts_with(entry->b->code, Text("userdata->"))) {
+            if (Text$starts_with(entry->b->code, Text("userdata->"), NULL)) {
                 Table$str_set(defer_env->locals, entry->name, entry->b);
             } else {
                 Text_t defer_name = Texts("defer$", String(++defer_id), "$", entry->name);
@@ -4254,7 +4254,7 @@ Text_t compile_function(env_t *env, Text_t name_code, ast_t *ast, Text_t *static
         definition = Texts(definition, wrapper);
     } else if (cache && cache->tag == Int) {
         assert(args);
-        OptionalInt64_t cache_size = Int64$parse(Text$from_str(Match(cache, Int)->str));
+        OptionalInt64_t cache_size = Int64$parse(Text$from_str(Match(cache, Int)->str), NULL);
         Text_t pop_code = EMPTY_TEXT;
         if (cache->tag == Int && !cache_size.is_none && cache_size.value > 0) {
             // FIXME: this currently just deletes the first entry, but this should be more like a
diff --git a/src/environment.c b/src/environment.c
index 93b5a16c..3faad24d 100644
--- a/src/environment.c
+++ b/src/environment.c
@@ -85,14 +85,15 @@ env_t *global_env(bool source_mapping)
         {"Abort", Type(AbortType), Text("void"), Text("Abort$info"), {}},
         {"Memory", Type(MemoryType), Text("Memory_t"), Text("Memory$info"), {}},
         {"Bool", Type(BoolType), Text("Bool_t"), Text("Bool$info"), TypedList(ns_entry_t,
-            {"parse", "Bool$parse", "func(text:Text -> Bool?)"},
+            {"parse", "Bool$parse", "func(text:Text, remainder:&Text? = none -> Bool?)"},
         )},
         {"Byte", Type(ByteType), Text("Byte_t"), Text("Byte$info"), TypedList(ns_entry_t,
-            {"max", "Byte$max", "Byte"},
             {"get_bit", "Byte$get_bit", "func(x:Byte, bit_index:Int -> Bool)"},
             {"hex", "Byte$hex", "func(byte:Byte, uppercase=yes, prefix=no -> Text)"},
             {"is_between", "Byte$is_between", "func(x:Byte, low:Byte, high:Byte -> Bool)"},
+            {"max", "Byte$max", "Byte"},
             {"min", "Byte$min", "Byte"},
+            {"parse", "Byte$parse", "func(text:Text, remainder:&Text? = none -> Byte?)"},
             {"to", "Byte$to", "func(first:Byte, last:Byte, step:Int8?=none -> func(->Byte?))"},
         )},
         {"Int", Type(BigIntType), Text("Int_t"), Text("Int$info"), TypedList(ns_entry_t,
@@ -118,7 +119,7 @@ env_t *global_env(bool source_mapping)
             {"next_prime", "Int$next_prime", "func(x:Int -> Int)"},
             {"octal", "Int$octal", "func(i:Int, digits=0, prefix=yes -> Text)"},
             {"onward", "Int$onward", "func(first:Int,step=1 -> func(->Int?))"},
-            {"parse", "Int$parse", "func(text:Text -> Int?)"},
+            {"parse", "Int$parse", "func(text:Text, remainder:&Text? = none -> Int?)"},
             {"plus", "Int$plus", "func(x,y:Int -> Int)"},
             {"power", "Int$power", "func(base:Int,exponent:Int -> Int)"},
 #if __GNU_MP_VERSION >= 6
@@ -137,7 +138,7 @@ env_t *global_env(bool source_mapping)
             {"clamped", "Int64$clamped", "func(x,low,high:Int64 -> Int64)"},
             {"divided_by", "Int64$divided_by", "func(x,y:Int64 -> Int64)"},
             {"gcd", "Int64$gcd", "func(x,y:Int64 -> Int64)"},
-            {"parse", "Int64$parse", "func(text:Text -> Int64?)"},
+            {"parse", "Int64$parse", "func(text:Text, remainder:&Text? = none -> Int64?)"},
             {"get_bit", "Int64$get_bit", "func(x:Int64, bit_index:Int -> Bool)"},
             {"hex", "Int64$hex", "func(i:Int64, digits=0, uppercase=yes, prefix=yes -> Text)"},
             {"is_between", "Int64$is_between", "func(x:Int64,low:Int64,high:Int64 -> Bool)"},
@@ -159,7 +160,7 @@ env_t *global_env(bool source_mapping)
             {"clamped", "Int32$clamped", "func(x,low,high:Int32 -> Int32)"},
             {"divided_by", "Int32$divided_by", "func(x,y:Int32 -> Int32)"},
             {"gcd", "Int32$gcd", "func(x,y:Int32 -> Int32)"},
-            {"parse", "Int32$parse", "func(text:Text -> Int32?)"},
+            {"parse", "Int32$parse", "func(text:Text, remainder:&Text? = none -> Int32?)"},
             {"get_bit", "Int32$get_bit", "func(x:Int32, bit_index:Int -> Bool)"},
             {"hex", "Int32$hex", "func(i:Int32, digits=0, uppercase=yes, prefix=yes -> Text)"},
             {"is_between", "Int32$is_between", "func(x:Int32,low:Int32,high:Int32 -> Bool)"},
@@ -181,7 +182,7 @@ env_t *global_env(bool source_mapping)
             {"clamped", "Int16$clamped", "func(x,low,high:Int16 -> Int16)"},
             {"divided_by", "Int16$divided_by", "func(x,y:Int16 -> Int16)"},
             {"gcd", "Int16$gcd", "func(x,y:Int16 -> Int16)"},
-            {"parse", "Int16$parse", "func(text:Text -> Int16?)"},
+            {"parse", "Int16$parse", "func(text:Text, remainder:&Text? = none -> Int16?)"},
             {"get_bit", "Int16$get_bit", "func(x:Int16, bit_index:Int -> Bool)"},
             {"hex", "Int16$hex", "func(i:Int16, digits=0, uppercase=yes, prefix=yes -> Text)"},
             {"is_between", "Int16$is_between", "func(x:Int16,low:Int16,high:Int16 -> Bool)"},
@@ -203,7 +204,7 @@ env_t *global_env(bool source_mapping)
             {"clamped", "Int8$clamped", "func(x,low,high:Int8 -> Int8)"},
             {"divided_by", "Int8$divided_by", "func(x,y:Int8 -> Int8)"},
             {"gcd", "Int8$gcd", "func(x,y:Int8 -> Int8)"},
-            {"parse", "Int8$parse", "func(text:Text -> Int8?)"},
+            {"parse", "Int8$parse", "func(text:Text, remainder:&Text? = none -> Int8?)"},
             {"get_bit", "Int8$get_bit", "func(x:Int8, bit_index:Int -> Bool)"},
             {"hex", "Int8$hex", "func(i:Int8, digits=0, uppercase=yes, prefix=yes -> Text)"},
             {"is_between", "Int8$is_between", "func(x:Int8,low:Int8,high:Int8 -> Bool)"},
@@ -238,7 +239,7 @@ env_t *global_env(bool source_mapping)
             {"INF", "(Num_t)(INFINITY)", "Num"},
             {"TAU", "(Num_t)(2.*M_PI)", "Num"},
             {"mix", "Num$mix", "func(amount,x,y:Num -> Num)"},
-            {"parse", "Num$parse", "func(text:Text -> Num?)"},
+            {"parse", "Num$parse", "func(text:Text, remainder:&Text? = none -> Num?)"},
             {"abs", "fabs", "func(n:Num -> Num)"},
             F_opt(acos), F_opt(acosh), F_opt(asin), F(asinh), F(atan), F_opt(atanh),
             F(cbrt), F(ceil), F_opt(cos), F(cosh), F(erf), F(erfc),
@@ -268,7 +269,7 @@ env_t *global_env(bool source_mapping)
             {"INF", "(Num32_t)(INFINITY)", "Num32"},
             {"TAU", "(Num32_t)(2.f*M_PI)", "Num32"},
             {"mix", "Num32$mix", "func(amount,x,y:Num32 -> Num32)"},
-            {"parse", "Num32$parse", "func(text:Text -> Num32?)"},
+            {"parse", "Num32$parse", "func(text:Text, remainder:&Text? = none -> Num32?)"},
             {"abs", "fabsf", "func(n:Num32 -> Num32)"},
             {"modulo", "Num32$mod", "func(x,y:Num32 -> Num32)"},
             {"modulo1", "Num32$mod1", "func(x,y:Num32 -> Num32)"},
@@ -345,7 +346,7 @@ env_t *global_env(bool source_mapping)
             {"bytes", "Text$utf8_bytes", "func(text:Text -> [Byte])"},
             {"caseless_equals", "Text$equal_ignoring_case", "func(a,b:Text, language='C' -> Bool)"},
             {"codepoint_names", "Text$codepoint_names", "func(text:Text -> [Text])"},
-            {"ends_with", "Text$ends_with", "func(text,suffix:Text -> Bool)"},
+            {"ends_with", "Text$ends_with", "func(text,suffix:Text, remainder:&Text? = none -> Bool)"},
             {"from", "Text$from", "func(text:Text, first:Int -> Text)"},
             {"from_bytes", "Text$from_bytes", "func(bytes:[Byte] -> Text?)"},
             {"from_c_string", "Text$from_str", "func(str:CString -> Text?)"},
@@ -368,7 +369,7 @@ env_t *global_env(bool source_mapping)
             {"slice", "Text$slice", "func(text:Text, from=1, to=-1 -> Text)"},
             {"split", "Text$split", "func(text:Text, delimiter='' -> [Text])"},
             {"split_any", "Text$split_any", "func(text:Text, delimiters=' \\t\\r\\n' -> [Text])"},
-            {"starts_with", "Text$starts_with", "func(text,prefix:Text -> Bool)"},
+            {"starts_with", "Text$starts_with", "func(text,prefix:Text, remainder:&Text? = none -> Bool)"},
             {"title", "Text$title", "func(text:Text, language='C' -> Text)"},
             {"to", "Text$to", "func(text:Text, last:Int -> Text)"},
             {"translate", "Text$translate", "func(text:Text, translations:{Text=Text} -> Text)"},
diff --git a/src/stdlib/bools.c b/src/stdlib/bools.c
index 66b7e209..85de0621 100644
--- a/src/stdlib/bools.c
+++ b/src/stdlib/bools.c
@@ -22,24 +22,37 @@ PUREFUNC public Text_t Bool$as_text(const void *b, bool colorize, const TypeInfo
         return *(Bool_t*)b ? Text("yes") : Text("no");
 }
 
-PUREFUNC public OptionalBool_t Bool$parse(Text_t text)
+static bool try_parse(Text_t text, Text_t target, bool target_value, Text_t *remainder, bool *result)
 {
-    Text_t lang = Text("C");
-    if (Text$equal_ignoring_case(text, Text("yes"), lang)
-        || Text$equal_ignoring_case(text, Text("on"), lang)
-        || Text$equal_ignoring_case(text, Text("true"), lang)
-        || Text$equal_ignoring_case(text, Text("1"), lang)) {
-        return yes;
-    } else if (Text$equal_ignoring_case(text, Text("no"), lang)
-        || Text$equal_ignoring_case(text, Text("off"), lang)
-        || Text$equal_ignoring_case(text, Text("false"), lang)
-        || Text$equal_ignoring_case(text, Text("0"), lang)) {
-        return no;
+    static const Text_t lang = Text("C");
+    if (text.length < target.length) return false;
+    Text_t prefix = Text$to(text, Int$from_int64(target.length));
+    if (Text$equal_ignoring_case(prefix, target, lang)) {
+        if (remainder) *remainder = Text$from(text, Int$from_int64(target.length + 1));
+        else if (text.length > target.length) return false;
+        *result = target_value;
+        return true;
     } else {
-        return NONE_BOOL;
+        return false;
     }
 }
 
+PUREFUNC public OptionalBool_t Bool$parse(Text_t text, Text_t *remainder)
+{
+    bool result;
+    if (try_parse(text, Text("yes"), true, remainder, &result)
+        || try_parse(text, Text("true"), true, remainder, &result)
+        || try_parse(text, Text("on"), true, remainder, &result)
+        || try_parse(text, Text("1"), true, remainder, &result)
+        || try_parse(text, Text("no"), false, remainder, &result)
+        || try_parse(text, Text("false"), false, remainder, &result)
+        || try_parse(text, Text("off"), false, remainder, &result)
+        || try_parse(text, Text("0"), false, remainder, &result))
+        return result;
+    else
+        return NONE_BOOL;
+}
+
 static bool Bool$is_none(const void *b, const TypeInfo_t *info)
 {
     (void)info;
diff --git a/src/stdlib/bools.h b/src/stdlib/bools.h
index 6d0300d5..ae6c5feb 100644
--- a/src/stdlib/bools.h
+++ b/src/stdlib/bools.h
@@ -13,7 +13,7 @@
 #define no (Bool_t)false
 
 PUREFUNC Text_t Bool$as_text(const void *b, bool colorize, const TypeInfo_t *type);
-OptionalBool_t Bool$parse(Text_t text);
+OptionalBool_t Bool$parse(Text_t text, Text_t *remainder);
 MACROLIKE Bool_t Bool$from_int(Int_t i) { return (i.small != 0); }
 MACROLIKE Bool_t Bool$from_int64(Int64_t i) { return (i != 0); }
 MACROLIKE Bool_t Bool$from_int32(Int32_t i) { return (i != 0); }
diff --git a/src/stdlib/bytes.c b/src/stdlib/bytes.c
index 48c8b93b..130a645f 100644
--- a/src/stdlib/bytes.c
+++ b/src/stdlib/bytes.c
@@ -3,6 +3,7 @@
 #include <stdint.h>
 
 #include "bytes.h"
+#include "integers.h"
 #include "stdlib.h"
 #include "text.h"
 #include "util.h"
@@ -29,6 +30,18 @@ public CONSTFUNC bool Byte$is_between(const Byte_t x, const Byte_t low, const By
     return low <= x && x <= high;
 }
 
+public OptionalByte_t Byte$parse(Text_t text, Text_t *remainder)
+{
+    OptionalInt_t full_int = Int$parse(text, remainder);
+    if (full_int.small != 0L
+        && Int$compare_value(full_int, I(0)) >= 0
+        && Int$compare_value(full_int, I(255)) <= 0) {
+        return (OptionalByte_t){.value=Byte$from_int(full_int, true)};
+    } else {
+        return NONE_BYTE;
+    }
+}
+
 public Text_t Byte$hex(Byte_t byte, bool uppercase, bool prefix) {
     struct Text_s text = {.tag=TEXT_ASCII};
     text.ascii = GC_MALLOC_ATOMIC(8);
diff --git a/src/stdlib/bytes.h b/src/stdlib/bytes.h
index e733c274..ab88b5bc 100644
--- a/src/stdlib/bytes.h
+++ b/src/stdlib/bytes.h
@@ -19,6 +19,7 @@ Byte_t Byte$from_int(Int_t i, bool truncate);
 Byte_t Byte$from_int64(int64_t i, bool truncate);
 Byte_t Byte$from_int32(int32_t i, bool truncate);
 Byte_t Byte$from_int16(int16_t i, bool truncate);
+OptionalByte_t Byte$parse(Text_t text, Text_t *remainder);
 Closure_t Byte$to(Byte_t first, Byte_t last, OptionalInt8_t step);
 MACROLIKE Byte_t Byte$from_int8(int8_t i) { return (Byte_t)i; }
 MACROLIKE Byte_t Byte$from_bool(bool b) { return (Byte_t)b; }
diff --git a/src/stdlib/integers.c b/src/stdlib/integers.c
index 018798ec..86be790d 100644
--- a/src/stdlib/integers.c
+++ b/src/stdlib/integers.c
@@ -424,8 +424,36 @@ public Int_t Int$from_str(const char *str) {
     return Int$from_mpz(i);
 }
 
-public OptionalInt_t Int$parse(Text_t text) {
-    return Int$from_str(Text$as_c_string(text));
+public OptionalInt_t Int$parse(Text_t text, Text_t *remainder) {
+    const char *str = Text$as_c_string(text);
+    mpz_t i;
+    int result;
+    if (strncmp(str, "0x", 2) == 0) {
+        const char *end = str + 2 + strcspn(str + 2, "0123456789abcdefABCDEF");
+        if (remainder) *remainder = Text$from_str(end);
+        else if (*end != '\0') return NONE_INT;
+        result = mpz_init_set_str(i, str + 2, 16);
+    } else if (strncmp(str, "0o", 2) == 0) {
+        const char *end = str + 2 + strcspn(str + 2, "01234567");
+        if (remainder) *remainder = Text$from_str(end);
+        else if (*end != '\0') return NONE_INT;
+        result = mpz_init_set_str(i, str + 2, 8);
+    } else if (strncmp(str, "0b", 2) == 0) {
+        const char *end = str + 2 + strcspn(str + 2, "01");
+        if (remainder) *remainder = Text$from_str(end);
+        else if (*end != '\0') return NONE_INT;
+        result = mpz_init_set_str(i, str + 2, 2);
+    } else {
+        const char *end = str + 2 + strcspn(str + 2, "0123456789");
+        if (remainder) *remainder = Text$from_str(end);
+        else if (*end != '\0') return NONE_INT;
+        result = mpz_init_set_str(i, str, 10);
+    }
+    if (result != 0) {
+        if (remainder) *remainder = text;
+        return NONE_INT;
+    }
+    return Int$from_mpz(i);
 }
 
 public bool Int$is_prime(Int_t x, Int_t reps)
@@ -670,8 +698,8 @@ public void Int32$deserialize(FILE *in, void *outval, List_t *pointers, const Ty
         range->step = step; \
         return (Closure_t){.fn=_next_##KindOfInt, .userdata=range}; \
     } \
-    public PUREFUNC Optional ## KindOfInt ## _t KindOfInt ## $parse(Text_t text) { \
-        OptionalInt_t full_int = Int$parse(text); \
+    public PUREFUNC Optional ## KindOfInt ## _t KindOfInt ## $parse(Text_t text, Text_t *remainder) { \
+        OptionalInt_t full_int = Int$parse(text, remainder); \
         if (full_int.small == 0L) return (Optional ## KindOfInt ## _t){.is_none=true}; \
         if (Int$compare_value(full_int, I(min_val)) < 0) { \
             return (Optional ## KindOfInt ## _t){.is_none=true}; \
diff --git a/src/stdlib/integers.h b/src/stdlib/integers.h
index beb26bd6..50ca485f 100644
--- a/src/stdlib/integers.h
+++ b/src/stdlib/integers.h
@@ -32,7 +32,7 @@
     bool type_name ## $get_bit(c_type x, Int_t bit_index); \
     Closure_t type_name ## $to(c_type first, c_type last, Optional ## type_name ## _t step); \
     Closure_t type_name ## $onward(c_type first, c_type step); \
-    PUREFUNC Optional ## type_name ## _t type_name ## $parse(Text_t text); \
+    PUREFUNC Optional ## type_name ## _t type_name ## $parse(Text_t text, Text_t *remainder); \
     CONSTFUNC bool type_name ## $is_between(const c_type x, const c_type low, const c_type high); \
     CONSTFUNC c_type type_name ## $clamped(c_type x, c_type min, c_type max); \
     MACROLIKE CONSTFUNC c_type type_name ## $from_byte(Byte_t b) { return (c_type)b; } \
@@ -101,7 +101,7 @@ Text_t Int$octal(Int_t i, Int_t digits, bool prefix);
 PUREFUNC Closure_t Int$to(Int_t first, Int_t last, OptionalInt_t step);
 PUREFUNC Closure_t Int$onward(Int_t first, Int_t step);
 OptionalInt_t Int$from_str(const char *str);
-OptionalInt_t Int$parse(Text_t text);
+OptionalInt_t Int$parse(Text_t text, Text_t *remainder);
 Int_t Int$abs(Int_t x);
 Int_t Int$power(Int_t base, Int_t exponent);
 Int_t Int$gcd(Int_t x, Int_t y);
diff --git a/src/stdlib/nums.c b/src/stdlib/nums.c
index 34fbb162..3775c8f4 100644
--- a/src/stdlib/nums.c
+++ b/src/stdlib/nums.c
@@ -98,14 +98,20 @@ public CONSTFUNC double Num$clamped(double x, double low, double high) {
     return (x <= low) ? low : (x >= high ? high : x);
 }
 
-public OptionalNum_t Num$parse(Text_t text) {
+public OptionalNum_t Num$parse(Text_t text, Text_t *remainder) {
     const char *str = Text$as_c_string(text);
     char *end = NULL;
     double d = strtod(str, &end);
-    if (end > str && end[0] == '\0')
+    if (end > str) {
+        if (remainder)
+            *remainder = Text$from_str(end);
+        else if (*end != '\0')
+            return nan("none");
         return d;
-    else
+    } else {
+        if (remainder) *remainder = text;
         return nan("none");
+    }
 }
 
 static bool Num$is_none(const void *n, const TypeInfo_t *info)
@@ -203,14 +209,19 @@ public CONSTFUNC float Num32$clamped(float x, float low, float high) {
     return (x <= low) ? low : (x >= high ? high : x);
 }
 
-public OptionalNum32_t Num32$parse(Text_t text) {
+public OptionalNum32_t Num32$parse(Text_t text, Text_t *remainder) {
     const char *str = Text$as_c_string(text);
     char *end = NULL;
     double d = strtod(str, &end);
-    if (end > str && end[0] == '\0')
+    if (end > str && end[0] == '\0') {
+        if (remainder) *remainder = Text$from_str(end);
+        else if (*end != '\0')
+            return nan("none");
         return d;
-    else
+    } else {
+        if (remainder) *remainder = text;
         return nan("none");
+    }
 }
 
 static bool Num32$is_none(const void *n, const TypeInfo_t *info)
diff --git a/src/stdlib/nums.h b/src/stdlib/nums.h
index fdd9e227..fe76d1c3 100644
--- a/src/stdlib/nums.h
+++ b/src/stdlib/nums.h
@@ -30,7 +30,7 @@ CONSTFUNC bool Num$finite(double n);
 CONSTFUNC bool Num$isnan(double n);
 double Num$nan(Text_t tag);
 CONSTFUNC double Num$mix(double amount, double x, double y);
-OptionalNum_t Num$parse(Text_t text);
+OptionalNum_t Num$parse(Text_t text, Text_t *remainder);
 CONSTFUNC bool Num$is_between(const double x, const double low, const double high);
 CONSTFUNC double Num$clamped(double x, double low, double high);
 MACROLIKE CONSTFUNC double Num$from_num32(Num32_t n) { return (double)n; }
@@ -83,7 +83,7 @@ CONSTFUNC bool Num32$isinf(float n);
 CONSTFUNC bool Num32$finite(float n);
 CONSTFUNC bool Num32$isnan(float n);
 CONSTFUNC float Num32$mix(float amount, float x, float y);
-OptionalNum32_t Num32$parse(Text_t text);
+OptionalNum32_t Num32$parse(Text_t text, Text_t *remainder);
 float Num32$nan(Text_t tag);
 CONSTFUNC bool Num32$is_between(const float x, const float low, const float high);
 CONSTFUNC float Num32$clamped(float x, float low, float high);
diff --git a/src/stdlib/paths.c b/src/stdlib/paths.c
index 94baf995..58702ec7 100644
--- a/src/stdlib/paths.c
+++ b/src/stdlib/paths.c
@@ -619,10 +619,10 @@ public bool Path$has_extension(Path_t path, Text_t extension)
     if (extension.length == 0)
         return !Text$has(Text$from(last, I(2)), Text(".")) || Text$equal_values(last, Text(".."));
 
-    if (!Text$starts_with(extension, Text(".")))
+    if (!Text$starts_with(extension, Text("."), NULL))
         extension = Texts(Text("."), extension);
 
-    return Text$ends_with(Text$from(last, I(2)), extension);
+    return Text$ends_with(Text$from(last, I(2)), extension, NULL);
 }
 
 public Path_t Path$child(Path_t path, Text_t name)
diff --git a/src/stdlib/stdlib.c b/src/stdlib/stdlib.c
index 2b4bd99c..02ccd710 100644
--- a/src/stdlib/stdlib.c
+++ b/src/stdlib/stdlib.c
@@ -90,37 +90,37 @@ static bool parse_single_arg(const TypeInfo_t *info, char *arg, void *dest)
             *(OptionalInt_t*)dest = parsed;
         return parsed.small != 0;
     } else if (info == &Int64$info) {
-        OptionalInt64_t parsed = Int64$parse(Text$from_str(arg));
+        OptionalInt64_t parsed = Int64$parse(Text$from_str(arg), NULL);
         if (!parsed.is_none)
             *(OptionalInt64_t*)dest = parsed;
         return !parsed.is_none;
     } else if (info == &Int32$info) {
-        OptionalInt32_t parsed = Int32$parse(Text$from_str(arg));
+        OptionalInt32_t parsed = Int32$parse(Text$from_str(arg), NULL);
         if (!parsed.is_none)
             *(OptionalInt32_t*)dest = parsed;
         return !parsed.is_none;
     } else if (info == &Int16$info) {
-        OptionalInt16_t parsed = Int16$parse(Text$from_str(arg));
+        OptionalInt16_t parsed = Int16$parse(Text$from_str(arg), NULL);
         if (!parsed.is_none)
             *(OptionalInt16_t*)dest = parsed;
         return !parsed.is_none;
     } else if (info == &Int8$info) {
-        OptionalInt8_t parsed = Int8$parse(Text$from_str(arg));
+        OptionalInt8_t parsed = Int8$parse(Text$from_str(arg), NULL);
         if (!parsed.is_none)
             *(OptionalInt8_t*)dest = parsed;
         return !parsed.is_none;
     } else if (info == &Bool$info) {
-        OptionalBool_t parsed = Bool$parse(Text$from_str(arg));
+        OptionalBool_t parsed = Bool$parse(Text$from_str(arg), NULL);
         if (parsed != NONE_BOOL)
             *(OptionalBool_t*)dest = parsed;
         return parsed != NONE_BOOL;
     } else if (info == &Num$info) {
-        OptionalNum_t parsed = Num$parse(Text$from_str(arg));
+        OptionalNum_t parsed = Num$parse(Text$from_str(arg), NULL);
         if (!isnan(parsed))
             *(OptionalNum_t*)dest = parsed;
         return !isnan(parsed);
     } else if (info == &Num32$info) {
-        OptionalNum32_t parsed = Num32$parse(Text$from_str(arg));
+        OptionalNum32_t parsed = Num32$parse(Text$from_str(arg), NULL);
         if (!isnan(parsed))
             *(OptionalNum32_t*)dest = parsed;
         return !isnan(parsed);
diff --git a/src/stdlib/text.c b/src/stdlib/text.c
index 80c267ed..8ef0874e 100644
--- a/src/stdlib/text.c
+++ b/src/stdlib/text.c
@@ -1102,30 +1102,42 @@ bool _matches(TextIter_t *text_state, TextIter_t *target_state, int64_t pos)
     return true;
 }
 
-PUREFUNC public bool Text$starts_with(Text_t text, Text_t prefix)
+PUREFUNC public bool Text$starts_with(Text_t text, Text_t prefix, Text_t *remainder)
 {
     if (text.length < prefix.length)
         return false;
     TextIter_t text_state = NEW_TEXT_ITER_STATE(text), prefix_state = NEW_TEXT_ITER_STATE(prefix);
-    return _matches(&text_state, &prefix_state, 0);
+    if (_matches(&text_state, &prefix_state, 0)) {
+        if (remainder) *remainder = Text$from(text, Int$from_int64(prefix.length + 1));
+        return true;
+    } else {
+        if (remainder) *remainder = text;
+        return false;
+    }
 }
 
-PUREFUNC public bool Text$ends_with(Text_t text, Text_t suffix)
+PUREFUNC public bool Text$ends_with(Text_t text, Text_t suffix, Text_t *remainder)
 {
     if (text.length < suffix.length)
         return false;
     TextIter_t text_state = NEW_TEXT_ITER_STATE(text), suffix_state = NEW_TEXT_ITER_STATE(suffix);
-    return _matches(&text_state, &suffix_state, text.length - suffix.length);
+    if (_matches(&text_state, &suffix_state, text.length - suffix.length)) {
+        if (remainder) *remainder = Text$to(text, Int$from_int64(text.length - suffix.length));
+        return true;
+    } else {
+        if (remainder) *remainder = text;
+        return false;
+    }
 }
 
 public Text_t Text$without_prefix(Text_t text, Text_t prefix)
 {
-    return Text$starts_with(text, prefix) ? Text$slice(text, I(prefix.length + 1), I(text.length)) : text;
+    return Text$starts_with(text, prefix, false) ? Text$slice(text, I(prefix.length + 1), I(text.length)) : text;
 }
 
 public Text_t Text$without_suffix(Text_t text, Text_t suffix)
 {
-    return Text$ends_with(text, suffix) ? Text$slice(text, I(1), I(text.length - suffix.length)) : text;
+    return Text$ends_with(text, suffix, false) ? Text$slice(text, I(1), I(text.length - suffix.length)) : text;
 }
 
 static bool _has_grapheme(TextIter_t *text, int32_t g)
diff --git a/src/stdlib/text.h b/src/stdlib/text.h
index 642a74b6..637a3db7 100644
--- a/src/stdlib/text.h
+++ b/src/stdlib/text.h
@@ -59,8 +59,8 @@ Text_t Text$lower(Text_t text, Text_t language);
 Text_t Text$title(Text_t text, Text_t language);
 Text_t Text$as_text(const void *text, bool colorize, const TypeInfo_t *info);
 Text_t Text$quoted(Text_t str, bool colorize, Text_t quotation_mark);
-PUREFUNC bool Text$starts_with(Text_t text, Text_t prefix);
-PUREFUNC bool Text$ends_with(Text_t text, Text_t suffix);
+PUREFUNC bool Text$starts_with(Text_t text, Text_t prefix, Text_t *remainder);
+PUREFUNC bool Text$ends_with(Text_t text, Text_t suffix, Text_t *remainder);
 Text_t Text$without_prefix(Text_t text, Text_t prefix);
 Text_t Text$without_suffix(Text_t text, Text_t suffix);
 Text_t Text$replace(Text_t text, Text_t target, Text_t replacement);
diff --git a/src/tomo.c b/src/tomo.c
index f60e7427..e105cb7a 100644
--- a/src/tomo.c
+++ b/src/tomo.c
@@ -709,11 +709,11 @@ time_t latest_included_modification_time(Path_t path)
     bool allow_dot_include = Path$has_extension(path, Text("s")) || Path$has_extension(path, Text("S"));
     for (Text_t line; (line=next_line(by_line.userdata)).length >= 0; ) {
         line = Text$trim(line, Text(" \t"), true, false);
-        if (!Text$starts_with(line, Text("#include")) && !(allow_dot_include && Text$starts_with(line, Text(".include"))))
+        if (!Text$starts_with(line, Text("#include"), NULL) && !(allow_dot_include && Text$starts_with(line, Text(".include"), NULL)))
             continue;
 
         // Check for `"` after `#include` or `.include` and some spaces:
-        if (!Text$starts_with(Text$trim(Text$from(line, I(9)), Text(" \t"), true, false), Text("\"")))
+        if (!Text$starts_with(Text$trim(Text$from(line, I(9)), Text(" \t"), true, false), Text("\""), NULL))
             continue;
 
         List_t chunks = Text$split(line, Text("\""));
diff --git a/src/typecheck.c b/src/typecheck.c
index 494c73d8..0ed2328f 100644
--- a/src/typecheck.c
+++ b/src/typecheck.c
@@ -1686,7 +1686,7 @@ PUREFUNC bool is_constant(env_t *env, ast_t *ast)
     case Bool: case Num: case None: return true;
     case Int: {
         DeclareMatch(info, ast, Int);
-        Int_t int_val = Int$parse(Text$from_str(info->str));
+        Int_t int_val = Int$parse(Text$from_str(info->str), NULL);
         if (int_val.small == 0) return false; // Failed to parse
         return (Int$compare_value(int_val, I(BIGGEST_SMALL_INT)) <= 0);
     }