Module Sexplib.Path

parse str

• Returns a substitution path represented by string str.

  Syntax:

  "." -> separates path elements; must be present at start of string.

  "[4]" -> specifies the 4th element in a tuple.

  "some_tag[4]" -> tries to match some_tag, then denotes its 4th argument.

  "name" -> denotes record field having name

  Example from test code:

  ".t.x.B1" -> choose record field with name t, then subfield x. Match this value against B, and denote its first argument.

• Raises Failure: if the path is syntactically invalid.

get ?path ?str sexp if path is provided, use it as path. Otherwise, if str is provided, parse it as a path. If neither is provided, assume an empty path.

• Returns the sub-expression from S-expression sexp denoted by the path.
• Raises Failure: if path is syntactically invalid or if the path structure clashes with the structure of the data.

replace ?path ?str sexp ~subst like get, but does not extract a sub-expression but substitutes it with subst.

• Returns resulting S-expression.
• Raises Failure: if path is syntactically invalid or if the path structure clashes with the structure of the data.

replace_no_path ~str sexp ~subst like replace, but does not take optional arguments. str must be specified.

• Raises Failure: if path is syntactically invalid or if the path structure clashes with the structure of the data.

subst_path sexp path

• Returns the tuple (subst, sub), where subst is a function that returns an S-expression in which the subexpression denoted by path in sexp has been substituted by its argument. sub is the denoted subexpression. Note that subst sub = sexp.
• Raises Failure: if path is syntactically invalid or if the path structure clashes with the structure of the data.

extract_pos n sexp

• Returns the tuple (subst, sub), where subst is a function that returns an S-expression in which the subexpression denoted at position n in sexp, which must be a list, has been substituted by value if the optional argument is Some value, or removes the denoted subexpression if the optional argument is None. sub is the denoted subexpression. Note that subst (Some sub) = sexp.
• Raises Failure: if the position cannot be resolved within the given S-expression.

extract_match tag n sexp

• Returns the tuple (subst, sub), where subst is a function that returns an S-expression in which the subexpression denoted by matching tag and taking its nth argument in sexp has been substituted by value if the argument is Some value, or removes the denoted subexpression if the optional argument is None. sub is the denoted subexpression. Note that subst (Some sub) = sexp.
• Raises Failure: if the S-expression does not represent a sum tag.

extract_rec name sexp

• Returns the tuple (subst, sub), where subst is a function that returns an S-expression in which the subexpression denoted by matching field name name in sexp has been substituted by its argument. sub is the denoted subexpression. Note that subst (Some sub) = sexp.
• Raises Failure: if the S-expression does not represent a record.