Merge: Added contributing guidelines and link from readme
[nit.git] / lib / core / text / abstract_text.nit
index e201e0c..e07e0d4 100644 (file)
@@ -305,23 +305,23 @@ abstract class Text
                end
        end
 
-       # Returns `true` if the string contains only Numeric values (and one "," or one "." character)
+       # Is this string in a valid numeric format compatible with `to_f`?
        #
        #     assert "123".is_numeric  == true
        #     assert "1.2".is_numeric  == true
        #     assert "-1.2".is_numeric == true
-       #     assert "1,2".is_numeric  == true
        #     assert "-1.23e-2".is_numeric == true
        #     assert "1..2".is_numeric == false
+       #     assert "".is_numeric     == false
        fun is_numeric: Bool
        do
-               var has_point_or_comma = false
+               var has_point = false
                var e_index = -1
                for i in [0..length[ do
                        var c = chars[i]
                        if not c.is_numeric then
-                               if (c == '.' or c == ',') and not has_point_or_comma then
-                                       has_point_or_comma = true
+                               if c == '.' and not has_point then
+                                       has_point = true
                                else if c == 'e' and e_index == -1 and i > 0 and i < length - 1 and chars[i-1] != '-' then
                                        e_index = i
                                else if c == '-' and i == e_index + 1 and i < length - 1 then
@@ -330,7 +330,7 @@ abstract class Text
                                end
                        end
                end
-               return true
+               return not is_empty
        end
 
        # Returns `true` if the string contains only Hex chars
@@ -495,18 +495,21 @@ abstract class Text
                end
        end
 
-       # Justify a self in a space of `length`
+       # Justify `self` in a space of `length`
        #
        # `left` is the space ratio on the left side.
        # * 0.0 for left-justified (no space at the left)
        # * 1.0 for right-justified (all spaces at the left)
        # * 0.5 for centered (half the spaces at the left)
        #
+       # `char`, or `' '` by default, is repeated to pad the empty space.
+       #
        # Examples
        #
        #     assert "hello".justify(10, 0.0)  == "hello     "
        #     assert "hello".justify(10, 1.0)  == "     hello"
        #     assert "hello".justify(10, 0.5)  == "  hello   "
+       #     assert "hello".justify(10, 0.5, '.') == "..hello..."
        #
        # If `length` is not enough, `self` is returned as is.
        #
@@ -515,13 +518,14 @@ abstract class Text
        # REQUIRE: `left >= 0.0 and left <= 1.0`
        # ENSURE: `self.length <= length implies result.length == length`
        # ENSURE: `self.length >= length implies result == self`
-       fun justify(length: Int, left: Float): String
+       fun justify(length: Int, left: Float, char: nullable Char): String
        do
+               var pad = (char or else ' ').to_s
                var diff = length - self.length
                if diff <= 0 then return to_s
                assert left >= 0.0 and left <= 1.0
                var before = (diff.to_f * left).to_i
-               return " " * before + self + " " * (diff-before)
+               return pad * before + self + pad * (diff-before)
        end
 
        # Mangle a string to be a unique string only made of alphanumeric characters and underscores.
@@ -586,10 +590,13 @@ abstract class Text
                return res.to_s
        end
 
-       # Escape " \ ' and non printable characters using the rules of literal C strings and characters
+       # Escape `"` `\` `'`, trigraphs and non printable characters using the rules of literal C strings and characters
        #
-       #     assert "abAB12<>&".escape_to_c         == "abAB12<>&"
+       #     assert "abAB12<>&".escape_to_c       == "abAB12<>&"
        #     assert "\n\"'\\".escape_to_c         == "\\n\\\"\\'\\\\"
+       #     assert "allo???!".escape_to_c        == "allo??\\?!"
+       #     assert "??=??/??'??(??)".escape_to_c == "?\\?=?\\?/??\\'?\\?(?\\?)"
+       #     assert "??!??<??>??-".escape_to_c    == "?\\?!?\\?<?\\?>?\\?-"
        #
        # Most non-printable characters (bellow ASCII 32) are escaped to an octal form `\nnn`.
        # Three digits are always used to avoid following digits to be interpreted as an element
@@ -613,9 +620,27 @@ abstract class Text
                                b.append("\\\'")
                        else if c == '\\' then
                                b.append("\\\\")
+                       else if c == '?' then
+                               # Escape if it is the last question mark of a ANSI C trigraph.
+                               var j = i + 1
+                               if j < length then
+                                       var next = chars[j]
+                                       # We ignore `??'` because it will be escaped as `??\'`.
+                                       if
+                                               next == '!' or
+                                               next == '(' or
+                                               next == ')' or
+                                               next == '-' or
+                                               next == '/' or
+                                               next == '<' or
+                                               next == '=' or
+                                               next == '>'
+                                       then b.add('\\')
+                               end
+                               b.add('?')
                        else if c.code_point < 32 then
                                b.add('\\')
-                               var oct = c.code_point.to_base(8, false)
+                               var oct = c.code_point.to_base(8)
                                # Force 3 octal digits since it is the
                                # maximum allowed in the C specification
                                if oct.length == 1 then
@@ -636,6 +661,7 @@ abstract class Text
        # The result might no be legal in C but be used in other languages
        #
        #     assert "ab|\{\}".escape_more_to_c("|\{\}") == "ab\\|\\\{\\\}"
+       #     assert "allo???!".escape_more_to_c("")     == "allo??\\?!"
        fun escape_more_to_c(chars: String): String
        do
                var b = new Buffer
@@ -689,7 +715,7 @@ abstract class Text
                                b.add('\\')
                                b.add(c)
                        else if c.code_point < 32 or c == ';' or c == '|' or c == '\\' or c == '=' then
-                               b.append("?{c.code_point.to_base(16, false)}")
+                               b.append("?{c.code_point.to_base(16)}")
                        else
                                b.add(c)
                        end
@@ -964,36 +990,46 @@ abstract class Text
                return hash_cache.as(not null)
        end
 
-       # Gives the formatted string back as a Nit string with `args` in place
+       # Format `self` by replacing each `%n` with the `n`th item of `args`
        #
-       #     assert "This %1 is a %2.".format("String", "formatted String") == "This String is a formatted String."
-       #     assert "\\%1 This string".format("String") == "\\%1 This string"
+       # The character `%` followed by something other than a number are left as is.
+       # To represent a `%` followed by a number, double the `%`, as in `%%7`.
+       #
+       #     assert "This %0 is a %1.".format("String", "formatted String") == "This String is a formatted String."
+       #     assert "Do not escape % nor %%1".format("unused") == "Do not escape % nor %1"
        fun format(args: Object...): String do
                var s = new Array[Text]
                var curr_st = 0
                var i = 0
                while i < length do
-                       # Skip escaped characters
-                       if self[i] == '\\' then
-                               i += 1
-                       # In case of format
-                       else if self[i] == '%' then
+                       if self[i] == '%' then
                                var fmt_st = i
                                i += 1
                                var ciph_st = i
                                while i < length and self[i].is_numeric do
                                        i += 1
                                end
-                               i -= 1
-                               var fmt_end = i
-                               var ciph_len = fmt_end - ciph_st + 1
 
-                               var arg_index = substring(ciph_st, ciph_len).to_i - 1
+                               var ciph_len = i - ciph_st
+                               if ciph_len == 0 then
+                                       # What follows '%' is not a number.
+                                       s.push substring(curr_st, i - curr_st)
+                                       if i < length and self[i] == '%' then
+                                               # Skip the next `%`
+                                               i += 1
+                                       end
+                                       curr_st = i
+                                       continue
+                               end
+
+                               var arg_index = substring(ciph_st, ciph_len).to_i
                                if arg_index >= args.length then continue
 
                                s.push substring(curr_st, fmt_st - curr_st)
                                s.push args[arg_index].to_s
-                               curr_st = i + 1
+
+                               curr_st = i
+                               i -= 1
                        end
                        i += 1
                end
@@ -1081,6 +1117,39 @@ abstract class Text
                end
        end
 
+       # Packs the content of a string in packs of `ln` chars.
+       # This variant ensures that only the last element might be smaller than `ln`
+       #
+       # ~~~nit
+       # var s = "abcdefghijklmnopqrstuvwxyz"
+       # assert s.pack_l(4) == ["abcd","efgh","ijkl","mnop","qrst","uvwx","yz"]
+       # ~~~
+       fun pack_l(ln: Int): Array[Text] do
+               var st = 0
+               var retarr = new Array[Text].with_capacity(length / ln + length % ln)
+               while st < length do
+                       retarr.add(substring(st, ln))
+                       st += ln
+               end
+               return retarr
+       end
+
+       # Packs the content of a string in packs of `ln` chars.
+       # This variant ensures that only the first element might be smaller than `ln`
+       #
+       # ~~~nit
+       # var s = "abcdefghijklmnopqrstuvwxyz"
+       # assert s.pack_r(4) == ["ab","cdef","ghij","klmn","opqr","stuv","wxyz"]
+       # ~~~
+       fun pack_r(ln: Int): Array[Text] do
+               var st = length
+               var retarr = new Array[Text].with_capacity(length / ln + length % ln)
+               while st >= 0 do
+                       retarr.add(substring(st - ln, ln))
+                       st -= ln
+               end
+               return retarr.reversed
+       end
 end
 
 # All kinds of array-based text representations.
@@ -1313,30 +1382,19 @@ abstract class String
        # Letters that follow a letter are lowercased
        # Letters that follow a non-letter are upcased.
        #
+       # If `keep_upper = true`, already uppercase letters are not lowercased.
+       #
        # SEE : `Char::is_letter` for the definition of letter.
        #
        #     assert "jAVASCRIPT".capitalized == "Javascript"
        #     assert "i am root".capitalized == "I Am Root"
        #     assert "ab_c -ab0c ab\nc".capitalized == "Ab_C -Ab0C Ab\nC"
-       fun capitalized: SELFTYPE do
+       #     assert "preserve my ACRONYMS".capitalized(keep_upper=true) == "Preserve My ACRONYMS"
+       fun capitalized(keep_upper: nullable Bool): SELFTYPE do
                if length == 0 then return self
 
                var buf = new Buffer.with_cap(length)
-
-               var curr = chars[0].to_upper
-               var prev = curr
-               buf[0] = curr
-
-               for i in [1 .. length[ do
-                       prev = curr
-                       curr = self[i]
-                       if prev.is_letter then
-                               buf[i] = curr.to_lower
-                       else
-                               buf[i] = curr.to_upper
-                       end
-               end
-
+               buf.capitalize(keep_upper=keep_upper, src=self)
                return buf.to_s
        end
 end
@@ -1431,6 +1489,13 @@ abstract class Buffer
        # Letters that follow a letter are lowercased
        # Letters that follow a non-letter are upcased.
        #
+       # If `keep_upper = true`, uppercase letters are not lowercased.
+       #
+       # When `src` is specified, this method reads from `src` instead of `self`
+       # but it still writes the result to the beginning of `self`.
+       # This requires `self` to have the capacity to receive all of the
+       # capitalized content of `src`.
+       #
        # SEE: `Char::is_letter` for the definition of a letter.
        #
        #     var b = new FlatBuffer.from("jAVAsCriPt")
@@ -1442,16 +1507,32 @@ abstract class Buffer
        #     b = new FlatBuffer.from("ab_c -ab0c ab\nc")
        #     b.capitalize
        #     assert b == "Ab_C -Ab0C Ab\nC"
-       fun capitalize do
+       #
+       #     b = new FlatBuffer.from("12345")
+       #     b.capitalize(src="foo")
+       #     assert b == "Foo45"
+       #
+       #     b = new FlatBuffer.from("preserve my ACRONYMS")
+       #     b.capitalize(keep_upper=true)
+       #     assert b == "Preserve My ACRONYMS"
+       fun capitalize(keep_upper: nullable Bool, src: nullable Text) do
+               src = src or else self
+               var length = src.length
                if length == 0 then return
-               var c = self[0].to_upper
+               keep_upper = keep_upper or else false
+
+               var c = src[0].to_upper
                self[0] = c
                var prev = c
                for i in [1 .. length[ do
                        prev = c
-                       c = self[i]
+                       c = src[i]
                        if prev.is_letter then
-                               self[i] = c.to_lower
+                               if keep_upper then
+                                       self[i] = c
+                               else
+                                       self[i] = c.to_lower
+                               end
                        else
                                self[i] = c.to_upper
                        end
@@ -1467,6 +1548,42 @@ abstract class Buffer
        # In Buffers, the internal sequence of character is mutable
        # Thus, `chars` can be used to modify the buffer.
        redef fun chars: Sequence[Char] is abstract
+
+       # Appends `length` chars from `s` starting at index `from`
+       #
+       # ~~~nit
+       #       var b = new Buffer
+       #       b.append_substring("abcde", 1, 2)
+       #       assert b == "bc"
+       #       b.append_substring("vwxyz", 2, 3)
+       #       assert b == "bcxyz"
+       #       b.append_substring("ABCDE", 4, 300)
+       #       assert b == "bcxyzE"
+       #       b.append_substring("VWXYZ", 400, 1)
+       #       assert b == "bcxyzE"
+       # ~~~
+       fun append_substring(s: Text, from, length: Int) do
+               if from < 0 then
+                       length += from
+                       from = 0
+               end
+               var ln = s.length
+               if (length + from) > ln then length = ln - from
+               if length <= 0 then return
+               append_substring_impl(s, from, length)
+       end
+
+       # Unsafe version of `append_substring` for performance
+       #
+       # NOTE: Use only if sure about `from` and `length`, no checks
+       # or bound recalculation is done
+       fun append_substring_impl(s: Text, from, length: Int) do
+               var pos = from
+               for i in [0 .. length[ do
+                       self.add s[pos]
+                       pos += 1
+               end
+       end
 end
 
 # View for chars on Buffer objects, extends Sequence
@@ -1554,14 +1671,14 @@ end
 redef class Int
 
        # Wrapper of strerror C function
-       private fun strerror_ext: NativeString `{ return strerror(self); `}
+       private fun strerror_ext: NativeString `{ return strerror((int)self); `}
 
        # Returns a string describing error number
        fun strerror: String do return strerror_ext.to_s
 
-       # Fill `s` with the digits in base `base` of `self` (and with the '-' sign if 'signed' and negative).
+       # Fill `s` with the digits in base `base` of `self` (and with the '-' sign if negative).
        # assume < to_c max const of char
-       private fun fill_buffer(s: Buffer, base: Int, signed: Bool)
+       private fun fill_buffer(s: Buffer, base: Int)
        do
                var n: Int
                # Sign
@@ -1593,14 +1710,30 @@ redef class Int
                snprintf(nstr, strlen, "%ld", self);
        `}
 
-       # return displayable int in base base and signed
-       fun to_base(base: Int, signed: Bool): String is abstract
+       # String representation of `self` in the given `base`
+       #
+       # ~~~
+       # assert 15.to_base(10) == "15"
+       # assert 15.to_base(16) == "f"
+       # assert 15.to_base(2) == "1111"
+       # assert (-10).to_base(3) == "-101"
+       # ~~~
+       fun to_base(base: Int): String
+       do
+               var l = digit_count(base)
+               var s = new Buffer
+               s.enlarge(l)
+               for x in [0..l[ do s.add(' ')
+               fill_buffer(s, base)
+               return s.to_s
+       end
+
 
        # return displayable int in hexadecimal
        #
        #     assert 1.to_hex  == "1"
        #     assert (-255).to_hex  == "-ff"
-       fun to_hex: String do return to_base(16,false)
+       fun to_hex: String do return to_base(16)
 end
 
 redef class Float
@@ -1692,8 +1825,20 @@ redef class Char
                return cp >= 0xD800 and cp <= 0xDFFF
        end
 
+       # Is `self` a UTF-16 high surrogate ?
+       fun is_hi_surrogate: Bool do
+               var cp = code_point
+               return cp >= 0xD800 and cp <= 0xDBFF
+       end
+
+       # Is `self` a UTF-16 low surrogate ?
+       fun is_lo_surrogate: Bool do
+               var cp = code_point
+               return cp >= 0xDC00 and cp <= 0xDFFF
+       end
+
        # Length of `self` in a UTF-8 String
-       private fun u8char_len: Int do
+       fun u8char_len: Int do
                var c = self.code_point
                if c < 0x80 then return 1
                if c <= 0x7FF then return 2
@@ -1877,7 +2022,11 @@ redef class Collection[E]
        #     assert [1, 2, 3].join(":")    == "1:2:3"
        #     assert [1..3].join(":")       == "1:2:3"
        #     assert [1..3].join            == "123"
-       fun join(separator: nullable Text): String
+       #
+       # if `last_separator` is given, then it is used to separate the last element.
+       #
+       #     assert [1, 2, 3, 4].join(", ", " and ")    == "1, 2, 3 and 4"
+       fun join(separator: nullable Text, last_separator: nullable Text): String
        do
                if is_empty then return ""
 
@@ -1888,13 +2037,19 @@ redef class Collection[E]
                var e = i.item
                if e != null then s.append(e.to_s)
 
+               if last_separator == null then last_separator = separator
+
                # Concat other items
                i.next
                while i.is_ok do
-                       if separator != null then s.append(separator)
                        e = i.item
-                       if e != null then s.append(e.to_s)
                        i.next
+                       if i.is_ok then
+                               if separator != null then s.append(separator)
+                       else
+                               if last_separator != null then s.append(last_separator)
+                       end
+                       if e != null then s.append(e.to_s)
                end
                return s.to_s
        end
@@ -1981,7 +2136,12 @@ end
 # see `alpha_comparator`
 private class AlphaComparator
        super Comparator
-       redef fun compare(a, b) do return a.to_s <=> b.to_s
+       redef fun compare(a, b) do
+               if a == b then return 0
+               if a == null then return -1
+               if b == null then return 1
+               return a.to_s <=> b.to_s
+       end
 end
 
 # Stateless comparator that naively use `to_s` to compare things.
@@ -2001,23 +2161,49 @@ do
 end
 
 redef class NativeString
-       # Returns `self` as a new String.
+       # Get a `String` from the data at `self` copied into Nit memory
+       #
+       # Require: `self` is a null-terminated string.
        fun to_s_with_copy: String is abstract
 
-       # Returns `self` as a String of `length`.
+       # Get a `String` from `length` bytes at `self`
+       #
+       # The result may point to the data at `self` or
+       # it may make a copy in Nit controlled memory.
+       # This method should only be used when `self` was allocated by the Nit GC,
+       # or when manually controlling the deallocation of `self`.
        fun to_s_with_length(length: Int): String is abstract
 
-       # Returns a new instance of `String` with self as `_items`
+       # Get a `String` from the raw `length` bytes at `self`
+       #
+       # The default value of `length` is the number of bytes before
+       # the first null character.
+       #
+       # The created `String` points to the data at `self`.
+       # This method should be used when `self` was allocated by the Nit GC,
+       # or when manually controlling the deallocation of `self`.
        #
-       # /!\: Does not clean the items for compliance with UTF-8,
-       # Use only if you know what you are doing
-       fun to_s_unsafe(len: nullable Int): String is abstract
+       # /!\: This service does not clean the items for compliance with UTF-8,
+       # use only when the data has already been verified as valid UTF-8.
+       fun to_s_unsafe(length: nullable Int): String is abstract
 
-       # Returns `self` as a String with `bytelen` and `length` set
+       # Get a `String` from the raw `bytelen` bytes at `self` with `unilen` Unicode characters
        #
-       # SEE: `abstract_text::Text` for more infos on the difference
-       # between `Text::bytelen` and `Text::length`
+       # The created `String` points to the data at `self`.
+       # This method should be used when `self` was allocated by the Nit GC,
+       # or when manually controlling the deallocation of `self`.
+       #
+       # /!\: This service does not clean the items for compliance with UTF-8,
+       # use only when the data has already been verified as valid UTF-8.
+       #
+       # SEE: `abstract_text::Text` for more info on the difference
+       # between `Text::bytelen` and `Text::length`.
        fun to_s_full(bytelen, unilen: Int): String is abstract
+
+       # Copies the content of `src` to `self`
+       #
+       # NOTE: `self` must be large enough to withold `self.bytelen` bytes
+       fun fill_from(src: Text) do src.copy_to_native(self, src.bytelen, 0, 0)
 end
 
 redef class NativeArray[E]