.h.level           # Heading level (1-6)
.h.depth           # Same as .h.level
.code.lang         # Code block language
.code.value        # Code block content
.link.url          # Link URL
.link.title        # Link title
.image.url         # Image URL
.image.alt         # Image alt text
.list.index        # List item index
.list.level        # Nesting level
.list.ordered      # Whether ordered list
.list.checked      # Checkbox state
.[0][0].row        # Table cell row
.[0][0].column     # Table cell column

mq '.h' file.md                         # All headings
mq '.h1' file.md                        # Only h1 headings
mq '.code' file.md                      # All code blocks
mq '.link.url' file.md                  # All URLs
mq '.image.alt' file.md                 # All image alt texts

mq 'select(.code)' file.md              # Only code blocks
mq 'select(!.code)' file.md             # Everything except code blocks
mq 'select(.h.level <= 2)' file.md      # h1 and h2 only
mq 'select(.code.lang == "rust")' file.md  # Rust code blocks only
mq 'select(contains("TODO"))' file.md   # Nodes containing "TODO"

mq '.h | to_text()' file.md             # Headings as plain text
mq '.code | to_text()' file.md          # Code block content as text
mq '.link | to_string()' file.md        # Links as strings

.h
| let link = to_link("#" + to_text(self), to_text(self), "")
| let level = .h.depth
| if (!is_none(level)): to_md_list(link, level - 1)

mq -A 'pluck(.code.value)' *.md         # Collect all code values
mq -S 's"\n---\n"' 'identity()' *.md    # Merge files with separator