Integrate Unicode escape handling into lexer/parser and remove unicode std dependency from JSON

.gitignore

@@ -13,3 +13,5 @@ build/
 # Generated runtime artifacts
 src/main/cod/src/bin/
 src/main/cod/src/idx/
+src/main/cod/demo/src/bin/
+src/main/cod/demo/src/idx/

src/main/cod/std/json/Json.cod

@@ -1,7 +1,5 @@
 unit json
 
-use {unicode}
-
 // JSON standard library for Coderive.
 // Supports parsing, mutation, and compact/pretty serialization of JSON values.
 share JsonValue {
@@ -303,12 +301,82 @@ share Json {
         if start + 5 >= raw.length { ~> (false) }
         if raw[start] != "\\" { ~> (false) }
         if raw[start + 1] != "u" { ~> (false) }
-        if !Unicode.isHexDigit(raw[start + 2]) { ~> (false) }
-        if !Unicode.isHexDigit(raw[start + 3]) { ~> (false) }
-        if !Unicode.isHexDigit(raw[start + 4]) { ~> (false) }
-        if !Unicode.isHexDigit(raw[start + 5]) { ~> (false) }
+        if !Json.isHexDigit(raw[start + 2]) { ~> (false) }
+        if !Json.isHexDigit(raw[start + 3]) { ~> (false) }
+        if !Json.isHexDigit(raw[start + 4]) { ~> (false) }
+        if !Json.isHexDigit(raw[start + 5]) { ~> (false) }
         ~> (true)
     }
+
+    share isDigit(ch: text) :: bool {
+        ~> (any[ch == "0", ch == "1", ch == "2", ch == "3", ch == "4", ch == "5", ch == "6", ch == "7", ch == "8", ch == "9"])
+    }
+
+    share isHexDigit(ch: text) :: bool {
+        ~> (any[
+            Json.isDigit(ch),
+            any[ch == "a", ch == "b", ch == "c", ch == "d", ch == "e", ch == "f"],
+            any[ch == "A", ch == "B", ch == "C", ch == "D", ch == "E", ch == "F"]
+        ])
+    }
+
+    share hexValue(ch: text) :: int {
+        if ch == "0" { ~> (0) }
+        if ch == "1" { ~> (1) }
+        if ch == "2" { ~> (2) }
+        if ch == "3" { ~> (3) }
+        if ch == "4" { ~> (4) }
+        if ch == "5" { ~> (5) }
+        if ch == "6" { ~> (6) }
+        if ch == "7" { ~> (7) }
+        if ch == "8" { ~> (8) }
+        if ch == "9" { ~> (9) }
+        if any[ch == "a", ch == "A"] { ~> (10) }
+        if any[ch == "b", ch == "B"] { ~> (11) }
+        if any[ch == "c", ch == "C"] { ~> (12) }
+        if any[ch == "d", ch == "D"] { ~> (13) }
+        if any[ch == "e", ch == "E"] { ~> (14) }
+        if any[ch == "f", ch == "F"] { ~> (15) }
+        ~> (-1)
+    }
+
+    share hexDigit(value: int) :: text {
+        if value == 0 { ~> ("0") }
+        if value == 1 { ~> ("1") }
+        if value == 2 { ~> ("2") }
+        if value == 3 { ~> ("3") }
+        if value == 4 { ~> ("4") }
+        if value == 5 { ~> ("5") }
+        if value == 6 { ~> ("6") }
+        if value == 7 { ~> ("7") }
+        if value == 8 { ~> ("8") }
+        if value == 9 { ~> ("9") }
+        if value == 10 { ~> ("A") }
+        if value == 11 { ~> ("B") }
+        if value == 12 { ~> ("C") }
+        if value == 13 { ~> ("D") }
+        if value == 14 { ~> ("E") }
+        ~> ("F")
+    }
+
+    share hex4(value: int) :: text {
+        x: int = value
+        if x < 0 { x = 0 }
+        if x > 65535 { x = x % 65536 }
+        d0 := (x / 4096) % 16
+        d1 := (x / 256) % 16
+        d2 := (x / 16) % 16
+        d3 := x % 16
+        ~> (Json.hexDigit(d0) + Json.hexDigit(d1) + Json.hexDigit(d2) + Json.hexDigit(d3))
+    }
+
+    share isHighSurrogate(unit: int) :: bool {
+        ~> (all[unit >= 55296, unit <= 56319])
+    }
+
+    share isLowSurrogate(unit: int) :: bool {
+        ~> (all[unit >= 56320, unit <= 57343])
+    }
 
     share indent(depth: int) :: text {
         textValue := ""
@@ -359,7 +427,7 @@ share JsonParser {
         if ch == "\"" { ~> (this.parseText()) }
         if ch == "[" { ~> (this.parseArray()) }
         if ch == "{" { ~> (this.parseObject()) }
-        if any[ch == "-", Unicode.isDigit(ch)] { ~> (this.parseNumber()) }
+        if any[ch == "-", Json.isDigit(ch)] { ~> (this.parseNumber()) }
 
         ~> (JsonValue.makeError("invalid json value at index " + this.index))
     }
@@ -431,9 +499,9 @@ share JsonParser {
                         ~> (JsonValue.makeError("invalid unicode escape at index " + this.index))
                     }
                     this.index = this.index + 4
-                    firstText := "\\u" + Unicode.hex4(firstUnit)
+                    firstText := "\\u" + Json.hex4(firstUnit)
 
-                    if Unicode.isHighSurrogate(firstUnit) {
+                    if Json.isHighSurrogate(firstUnit) {
                         if this.index + 5 >= this.source.length {
                             ~> (JsonValue.makeError("missing low surrogate at index " + this.index))
                         }
@@ -442,15 +510,15 @@ share JsonParser {
                         }
                         this.index = this.index + 2
                         secondUnit := this.parseHex4At(this.index)
-                        if any[secondUnit < 0, !Unicode.isLowSurrogate(secondUnit)] {
+                        if any[secondUnit < 0, !Json.isLowSurrogate(secondUnit)] {
                             ~> (JsonValue.makeError("invalid low surrogate at index " + this.index))
                         }
                         this.index = this.index + 4
-                        outText = outText + firstText + "\\u" + Unicode.hex4(secondUnit)
+                        outText = outText + firstText + "\\u" + Json.hex4(secondUnit)
                         continue
                     }
 
-                    if Unicode.isLowSurrogate(firstUnit) {
+                    if Json.isLowSurrogate(firstUnit) {
                         ~> (JsonValue.makeError("unexpected low surrogate at index " + (this.index - 4)))
                     }
 
@@ -480,24 +548,24 @@ share JsonParser {
         if this.source[this.index] == "0" {
             this.index = this.index + 1
         } else {
-            if !Unicode.isDigit(this.source[this.index]) {
+            if !Json.isDigit(this.source[this.index]) {
                 ~> (JsonValue.makeError("invalid number at index " + start))
             }
             for i of this.index to this.source.length {
                 if this.index >= this.source.length { break }
-                if !Unicode.isDigit(this.source[this.index]) { break }
+                if !Json.isDigit(this.source[this.index]) { break }
                 this.index = this.index + 1
             }
         }
 
         if all[this.index < this.source.length, this.source[this.index] == "."] {
             this.index = this.index + 1
-            if any[this.index >= this.source.length, !Unicode.isDigit(this.source[this.index])] {
+            if any[this.index >= this.source.length, !Json.isDigit(this.source[this.index])] {
                 ~> (JsonValue.makeError("invalid number fraction at index " + start))
             }
             for i of this.index to this.source.length {
                 if this.index >= this.source.length { break }
-                if !Unicode.isDigit(this.source[this.index]) { break }
+                if !Json.isDigit(this.source[this.index]) { break }
                 this.index = this.index + 1
             }
         }
@@ -507,12 +575,12 @@ share JsonParser {
             if all[this.index < this.source.length, any[this.source[this.index] == "+", this.source[this.index] == "-"]] {
                 this.index = this.index + 1
             }
-            if any[this.index >= this.source.length, !Unicode.isDigit(this.source[this.index])] {
+            if any[this.index >= this.source.length, !Json.isDigit(this.source[this.index])] {
                 ~> (JsonValue.makeError("invalid number exponent at index " + start))
             }
             for i of this.index to this.source.length {
                 if this.index >= this.source.length { break }
-                if !Unicode.isDigit(this.source[this.index]) { break }
+                if !Json.isDigit(this.source[this.index]) { break }
                 this.index = this.index + 1
             }
         }
@@ -648,7 +716,7 @@ share JsonParser {
         if start + 3 >= this.source.length { ~> (-1) }
         value: int = 0
         for j of 0 to 3 {
-            digit := Unicode.hexValue(this.source[start + j])
+            digit := Json.hexValue(this.source[start + j])
             if digit < 0 { ~> (-1) }
             value = value * 16 + digit
         }