角色通过弦循环时被跳过

Question

我正在制作一种爱好编程语言，而我的Lexer在阅读整数时存在问题。

这是当前字符在数字字符串列表中的代码：

integers = "1234567890"

elif currentChar in integers:
                res = ""

                while pos < length and src[pos] in integers:
                    print(src[pos])
                    res += src[pos]

                    pos += 1
                    column += 1
                
                pos += 1
                column += 1
                tokens.append({"type": "INTEGER", "value": res})

如果您需要整个主Lexer函数，则是：

def tokenize(self):
        tokens = []
        
        pos = 0
        line = 1
        column = 1

        src = self.src

        length = len(src)

        varChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_"
        integers = "1234567890"

        KEYWORDS = ["print"]

        while pos < length:
            currentChar = src[pos]

            if currentChar == " ":
                pos += 1
                column += 1
                continue
            elif currentChar == "\n":
                line += 1
                column = 0
                pos += 1
                continue
            elif currentChar == '"':
                pos += 1
                column += 1

                res = ""

                while pos < length and src[pos] != '"':
                    res += src[pos]

                    pos += 1
                    column += 1

                try:
                    if src[pos] != '"':
                        return [], f"Unterminated string at line {line}, column {column}"
                except IndexError:
                    if src[pos - 1] != '"':
                        return [], f"Unterminated string at line {line}, column {column}"
                
                pos += 1
                column += 1
                tokens.append({"type": "STRING", "value": res})
            elif currentChar in varChars:
                pos += 1
                column += 1

                res = currentChar

                while pos < length and src[pos] in varChars:
                    res += src[pos]

                    pos += 1
                    column += 1

                if res not in KEYWORDS:
                    tokens.append({"type": "VARIABLE_NAME", "value": res})
                elif res in KEYWORDS:
                    tokens.append({"type": "KEYWORD", "value": res})
            elif currentChar == "=":
                pos += 1
                column += 1
                tokens.append({"type": "OPERATOR", "value": currentChar})
            elif currentChar in integers:
                res = ""

                while pos < length and src[pos] in integers:
                    print(src[pos])
                    res += src[pos]

                    pos += 1
                    column += 1

                tokens.append({"type": "INTEGER", "value": res})
            elif currentChar == "(":
                pos += 1
                column += 1
                tokens.append({"type": "OPEN_PAREN", "value": currentChar})
            elif currentChar == ")":
                pos += 1
                column += 1
                tokens.append({"type": "CLOSE_PAREN", "value": currentChar})
            elif currentChar == ";":
                res = ""

                pos += 1
                column += 1

                while pos < length and src[pos] != "\n":
                    res += src[pos]

                    pos += 1
                    column += 1
                
                pos += 1
                column += 1
                tokens.append({"type": "COMMENT", "value": res})
            else:
                return [], f"Unexpected character {currentChar} at line {line}, column {column}"

PS：POS：POS是SRC中的当前索引，而SRC是代码。

当我最终到达解析器的结尾时，它说我缺少一个角色，在数字结束后总是是角色。

例如：

print(10)

在此代码中，闭合括号将由Lexer跳过。

任何帮助将不胜感激！

Answer 1

您会意外地在循环外再次递增自己的位置。

     while pos < length and src[pos] in integers:
            print(src[pos])
            res += src[pos]

            pos += 1
            column += 1
        
        pos += 1 # <-------------------
        column += 1 # <----------------

当您的Lexer进入该循环的最后一次迭代时，它会读取最终数字，将其递增，然后再次递增，然后再跳过角色。