Provides the locations of LaTeX commands with mandatory arguments.
locate_mandatory_LaTeX_argument(
tex_lines,
command_name,
n = 1L,
parsed_doc = NULL
)A character vector of a LaTeX document,
-- for example as obtained from readLines("mydoc.tex").
The command (without backslash) whose arguments' locations are desired.
Integer vector: which argument(s) to locate. If n = NA, the n-th argument
positions for all n.
The result of parse_tex(tex_lines).