338 lines
11 KiB
Python
338 lines
11 KiB
Python
import re
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LEFT_PATTERN = re.compile(r'(\\left)(\S*)')
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RIGHT_PATTERN = re.compile(r'(\\right)(\S*)')
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LEFT_COUNT_PATTERN = re.compile(r'\\left(?![a-zA-Z])')
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RIGHT_COUNT_PATTERN = re.compile(r'\\right(?![a-zA-Z])')
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LEFT_RIGHT_REMOVE_PATTERN = re.compile(r'\\left\.?|\\right\.?')
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def fix_latex_left_right(s, fix_delimiter=True):
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"""
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修复LaTeX中的\\left和\\right命令
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1. 确保它们后面跟有效分隔符
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2. 平衡\\left和\\right的数量
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"""
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# 白名单分隔符
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valid_delims_list = [r'(', r')', r'[', r']', r'{', r'}', r'/', r'|',
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r'\{', r'\}', r'\lceil', r'\rceil', r'\lfloor',
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r'\rfloor', r'\backslash', r'\uparrow', r'\downarrow',
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r'\Uparrow', r'\Downarrow', r'\|', r'\.']
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# 为\left后缺失有效分隔符的情况添加点
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def fix_delim(match, is_left=True):
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cmd = match.group(1) # \left 或 \right
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rest = match.group(2) if len(match.groups()) > 1 else ""
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if not rest or rest not in valid_delims_list:
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return cmd + "."
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return match.group(0)
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# 使用更精确的模式匹配\left和\right命令
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# 确保它们是独立的命令，不是其他命令的一部分
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# 使用预编译正则和统一回调函数
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if fix_delimiter:
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s = LEFT_PATTERN.sub(lambda m: fix_delim(m, True), s)
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s = RIGHT_PATTERN.sub(lambda m: fix_delim(m, False), s)
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# 更精确地计算\left和\right的数量
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left_count = len(LEFT_COUNT_PATTERN.findall(s)) # 不匹配\lefteqn等
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right_count = len(RIGHT_COUNT_PATTERN.findall(s)) # 不匹配\rightarrow等
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if left_count == right_count:
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# 如果数量相等，检查是否在同一组
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return fix_left_right_pairs(s)
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# return s
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else:
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# 如果数量不等，移除所有\left和\right
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# logger.debug(f"latex:{s}")
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# logger.warning(f"left_count: {left_count}, right_count: {right_count}")
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return LEFT_RIGHT_REMOVE_PATTERN.sub('', s)
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def fix_left_right_pairs(latex_formula):
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"""
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检测并修复LaTeX公式中\\left和\\right不在同一组的情况
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Args:
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latex_formula (str): 输入的LaTeX公式
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Returns:
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str: 修复后的LaTeX公式
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"""
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# 用于跟踪花括号嵌套层级
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brace_stack = []
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# 用于存储\left信息: (位置, 深度, 分隔符)
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left_stack = []
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# 存储需要调整的\right信息: (开始位置, 结束位置, 目标位置)
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adjustments = []
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i = 0
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while i < len(latex_formula):
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# 检查是否是转义字符
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if i > 0 and latex_formula[i - 1] == '\\':
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backslash_count = 0
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j = i - 1
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while j >= 0 and latex_formula[j] == '\\':
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backslash_count += 1
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j -= 1
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if backslash_count % 2 == 1:
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i += 1
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continue
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# 检测\left命令
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if i + 5 < len(latex_formula) and latex_formula[i:i + 5] == "\\left" and i + 5 < len(latex_formula):
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delimiter = latex_formula[i + 5]
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left_stack.append((i, len(brace_stack), delimiter))
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i += 6 # 跳过\left和分隔符
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continue
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# 检测\right命令
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elif i + 6 < len(latex_formula) and latex_formula[i:i + 6] == "\\right" and i + 6 < len(latex_formula):
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delimiter = latex_formula[i + 6]
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if left_stack:
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left_pos, left_depth, left_delim = left_stack.pop()
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# 如果\left和\right不在同一花括号深度
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if left_depth != len(brace_stack):
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# 找到\left所在花括号组的结束位置
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target_pos = find_group_end(latex_formula, left_pos, left_depth)
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if target_pos != -1:
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# 记录需要移动的\right
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adjustments.append((i, i + 7, target_pos))
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i += 7 # 跳过\right和分隔符
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continue
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# 处理花括号
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if latex_formula[i] == '{':
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brace_stack.append(i)
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elif latex_formula[i] == '}':
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if brace_stack:
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brace_stack.pop()
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i += 1
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# 应用调整，从后向前处理以避免索引变化
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if not adjustments:
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return latex_formula
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result = list(latex_formula)
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adjustments.sort(reverse=True, key=lambda x: x[0])
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for start, end, target in adjustments:
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# 提取\right部分
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right_part = result[start:end]
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# 从原位置删除
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del result[start:end]
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# 在目标位置插入
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result.insert(target, ''.join(right_part))
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return ''.join(result)
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def find_group_end(text, pos, depth):
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"""查找特定深度的花括号组的结束位置"""
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current_depth = depth
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i = pos
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while i < len(text):
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if text[i] == '{' and (i == 0 or not is_escaped(text, i)):
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current_depth += 1
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elif text[i] == '}' and (i == 0 or not is_escaped(text, i)):
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current_depth -= 1
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if current_depth < depth:
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return i
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i += 1
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return -1 # 未找到对应结束位置
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def is_escaped(text, pos):
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"""检查字符是否被转义"""
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backslash_count = 0
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j = pos - 1
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while j >= 0 and text[j] == '\\':
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backslash_count += 1
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j -= 1
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return backslash_count % 2 == 1
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def fix_unbalanced_braces(latex_formula):
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"""
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检测LaTeX公式中的花括号是否闭合，并删除无法配对的花括号
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Args:
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latex_formula (str): 输入的LaTeX公式
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Returns:
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str: 删除无法配对的花括号后的LaTeX公式
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"""
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stack = [] # 存储左括号的索引
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unmatched = set() # 存储不匹配括号的索引
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i = 0
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while i < len(latex_formula):
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# 检查是否是转义的花括号
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if latex_formula[i] in ['{', '}']:
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# 计算前面连续的反斜杠数量
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backslash_count = 0
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j = i - 1
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while j >= 0 and latex_formula[j] == '\\':
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backslash_count += 1
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j -= 1
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# 如果前面有奇数个反斜杠，则该花括号是转义的，不参与匹配
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if backslash_count % 2 == 1:
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i += 1
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continue
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# 否则，该花括号参与匹配
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if latex_formula[i] == '{':
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stack.append(i)
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else: # latex_formula[i] == '}'
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if stack: # 有对应的左括号
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stack.pop()
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else: # 没有对应的左括号
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unmatched.add(i)
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i += 1
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# 所有未匹配的左括号
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unmatched.update(stack)
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# 构建新字符串，删除不匹配的括号
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return ''.join(char for i, char in enumerate(latex_formula) if i not in unmatched)
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def process_latex(input_string):
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"""
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处理LaTeX公式中的反斜杠：
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1. 如果\后跟特殊字符(#$%&~_^\\{})或空格，保持不变
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2. 如果\后跟两个小写字母，保持不变
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3. 其他情况，在\后添加空格
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Args:
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input_string (str): 输入的LaTeX公式
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Returns:
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str: 处理后的LaTeX公式
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"""
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def replace_func(match):
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# 获取\后面的字符
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next_char = match.group(1)
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# 如果是特殊字符或空格，保持不变
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if next_char in "#$%&~_^|\\{} \t\n\r\v\f":
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return match.group(0)
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# 如果是字母，检查下一个字符
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if 'a' <= next_char <= 'z' or 'A' <= next_char <= 'Z':
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pos = match.start() + 2 # \x后的位置
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if pos < len(input_string) and ('a' <= input_string[pos] <= 'z' or 'A' <= input_string[pos] <= 'Z'):
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# 下一个字符也是字母，保持不变
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return match.group(0)
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# 其他情况，在\后添加空格
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return '\\' + ' ' + next_char
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# 匹配\后面跟一个字符的情况
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pattern = r'\\(.)'
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return re.sub(pattern, replace_func, input_string)
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# 常见的在KaTeX/MathJax中可用的数学环境
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ENV_TYPES = ['array', 'matrix', 'pmatrix', 'bmatrix', 'vmatrix',
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'Bmatrix', 'Vmatrix', 'cases', 'aligned', 'gathered', 'align', 'align*']
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ENV_BEGIN_PATTERNS = {env: re.compile(r'\\begin\{' + env + r'\}') for env in ENV_TYPES}
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ENV_END_PATTERNS = {env: re.compile(r'\\end\{' + env + r'\}') for env in ENV_TYPES}
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ENV_FORMAT_PATTERNS = {env: re.compile(r'\\begin\{' + env + r'\}\{([^}]*)\}') for env in ENV_TYPES}
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def fix_latex_environments(s):
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"""
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检测LaTeX中环境（如array）的\\begin和\\end是否匹配
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1. 如果缺少\\begin标签则在开头添加
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2. 如果缺少\\end标签则在末尾添加
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"""
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for env in ENV_TYPES:
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begin_count = len(ENV_BEGIN_PATTERNS[env].findall(s))
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end_count = len(ENV_END_PATTERNS[env].findall(s))
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if begin_count != end_count:
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if end_count > begin_count:
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format_match = ENV_FORMAT_PATTERNS[env].search(s)
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default_format = '{c}' if env == 'array' else ''
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format_str = '{' + format_match.group(1) + '}' if format_match else default_format
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missing_count = end_count - begin_count
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begin_command = '\\begin{' + env + '}' + format_str + ' '
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s = begin_command * missing_count + s
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else:
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missing_count = begin_count - end_count
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s = s + (' \\end{' + env + '}') * missing_count
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return s
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REPLACEMENTS_PATTERNS = {
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re.compile(r'\\underbar'): r'\\underline',
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re.compile(r'\\Bar'): r'\\hat',
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re.compile(r'\\Hat'): r'\\hat',
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re.compile(r'\\Tilde'): r'\\tilde',
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re.compile(r'\\slash'): r'/',
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re.compile(r'\\textperthousand'): r'‰',
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re.compile(r'\\sun'): r'☉',
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re.compile(r'\\textunderscore'): r'\\_',
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re.compile(r'\\fint'): r'⨏',
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re.compile(r'\\up '): r'\\ ',
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re.compile(r'\\vline = '): r'\\models ',
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re.compile(r'\\vDash '): r'\\models ',
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re.compile(r'\\sq \\sqcup '): r'\\square ',
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re.compile(r'\\copyright'): r'©',
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}
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QQUAD_PATTERN = re.compile(r'\\qquad(?!\s)')
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def remove_up_commands(s: str):
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"""Remove unnecessary up commands from LaTeX code."""
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UP_PATTERN = re.compile(r'\\up([a-zA-Z]+)')
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s = UP_PATTERN.sub(
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lambda m: m.group(0) if m.group(1) in ["arrow", "downarrow", "lus", "silon"] else f"\\{m.group(1)}", s
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)
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return s
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def remove_unsupported_commands(s: str):
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"""Remove unsupported LaTeX commands."""
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COMMANDS_TO_REMOVE_PATTERN = re.compile(
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r'\\(?:lefteqn|boldmath|ensuremath|centering|textsubscript|sides|textsl|textcent|emph|protect|null)')
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s = COMMANDS_TO_REMOVE_PATTERN.sub('', s)
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return s
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def latex_rm_whitespace(s: str):
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"""Remove unnecessary whitespace from LaTeX code."""
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s = fix_unbalanced_braces(s)
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s = fix_latex_left_right(s)
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s = fix_latex_environments(s)
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s = remove_up_commands(s)
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s = remove_unsupported_commands(s)
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# 应用所有替换
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for pattern, replacement in REPLACEMENTS_PATTERNS.items():
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s = pattern.sub(replacement, s)
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# 处理LaTeX中的反斜杠和空格
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s = process_latex(s)
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# \qquad后补空格
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s = QQUAD_PATTERN.sub(r'\\qquad ', s)
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# 如果字符串以反斜杠结尾，去掉最后的反斜杠
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while s.endswith('\\'):
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s = s[:-1]
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return s |