嵌套大括号/方括号组解析：含可选/重复段的文件解析问询

Hey there, let's break down the HL7 segment structure you're trying to parse step by step. First up, here's the exact format you're working with:

MSH [ PD1 ] [{ ROL }] [ { ROL } ] [ { PR1 [{ ROL }] } ] [ { IN1 [ IN2 ] [{ IN3 }] } ] [ ACC ]

Key Symbol Definitions #

Let's clarify what each marker in this format means:

• 3-character alphanumeric codes: Each one represents a single HL7 Segment (the core data blocks of HL7 messages, e.g., MSH, PD1).
• [ SEGMENT ]: Marks an Optional Segment — this segment might appear in the message, but it's not required.
• { SEGMENT }: Marks a Repeating Segment — this segment can show up multiple times in a row.
• [{ SEGMENT }]: Marks an Optional Repeating Segment — this segment is optional, and if it does appear, it can repeat multiple times.
• Nested combinations: Optional ([]) and repeating ({}) groups can be nested, like in the { PR1 [{ ROL }] } example. Here, the PR1 segment is required whenever this repeating group is present, and each PR1 can optionally have one or more ROL segments attached to it. This nesting lets HL7 handle complex, flexible data scenarios.

内容的提问来源于stack exchange，提问作者Integration