Add lower and upper functions

scripts/gen_case_mappings.py

@@ -0,0 +1,86 @@
+#!/usr/bin/env python3
+
+
+def switch_cases(values):
+    result = []
+    i = 0
+    while i < len(values):
+        start = values[i]
+        case = (start, start)
+        j = i + 1
+        while j < len(values):
+            end = values[j]
+            if (end - start) != (j - i):
+                i = j
+                break
+            case = (start, end)
+            j += 1
+        if i != j:
+            i += 1
+        result.append(case)
+    return result
+
+
+def write_testing_func(output, func_name, char_set):
+    output.write('pub fn {0}(code_point: u32) bool {{\n'.format(func_name))
+    output.write('    return switch (code_point) {\n')
+    cases = switch_cases(sorted(char_set))
+    for case in cases:
+        if case != cases[0]:
+            output.write(',\n')
+        start, end = hex(case[0]), hex(case[1])
+        if start == end:
+            output.write('        {0}'.format(start))
+        else:
+            output.write('        {0} ... {1}'.format(start, end))
+    output.write(' => true,\n')
+    output.write('        else => false,\n')
+    output.write('    };\n')
+    output.write('}\n')
+
+
+def write_conversion_func(output, func_name, mapping):
+    output.write('pub fn {0}(code_point: u32) u32 {{\n'.format(func_name))
+    output.write('    return switch (code_point) {\n')
+    for key in sorted(mapping.keys()):
+        output.write('        {0} => {1},\n'.format(hex(key), hex(mapping[key])))
+    output.write('        else => code_point,\n')
+    output.write('    };\n')
+    output.write('}\n')
+
+
+def main():
+    uppercase = set()
+    lowercase = set()
+    to_upper = {}
+    to_lower = {}
+    with open('UnicodeData.txt') as input, \
+         open('case_mapping.zig', 'w') as output:
+        output.write(
+            '// This code is generated from UnicodeData.txt using ' +
+            __file__ + '\n\n')
+        for line in input:
+            fields = line.split(';')
+            code_point = int(fields[0].strip(), 16)
+            uppercase_mapping = fields[12].strip()
+            lowercase_mapping = fields[13].strip()
+            if uppercase_mapping:
+                upper_code_point = int(uppercase_mapping, 16)
+                uppercase.add(upper_code_point)
+                to_upper[code_point] = upper_code_point
+            if lowercase_mapping:
+                lower_code_point = int(lowercase_mapping, 16)
+                lowercase.add(lower_code_point)
+                to_lower[code_point] = lower_code_point
+
+        write_testing_func(output, 'isLower', lowercase)
+        output.write('\n')
+        write_testing_func(output, 'isUpper', uppercase)
+        output.write('\n')
+        write_conversion_func(output, 'toLower', to_lower)
+        output.write('\n')
+        write_conversion_func(output, 'toUpper', to_upper)
+
+
+if __name__ == '__main__':
+    main()