This module is a first start of what should become a full-featured
pretty printer for Prolog terms with many options and parameters.
Eventually, it should replace portray_clause/1 and various other
- To be done
- - This is just a quicky. We need proper handling of portray/1, avoid
printing very long terms multiple times, spacing (around operators),
- - Use a record for the option-processing.
- - The current approach is far too simple, often resulting in illegal
- print_term(+Term, +Options) is det
- Pretty print a Prolog term. The following options are processed:
- Define the output stream. Default is
- Width of a line. If the output is a tty and tty_size/2
can produce a size the default is the number of columns
minus 8. Otherwise the default is 72 characters. If the
Column is unbound it is unified with the computed value.
- Left margin for continuation lines. Default is the current
line position or
0 if that is not available.
- Distance between tab-stops. Default is 8 characters.
- Defines how arguments of compound terms are placed. Defined
Simply place them left to right (no line-breaks)
Place them vertically, aligned with the open bracket (not
As horizontal if line-width is not exceeded, vertical
- An integer
Place them vertically aligned, <N> spaces to the right of
the beginning of the head.
- This is the inverse of the write_term/3 option
Default is to respect them.
- List of options passed to write_term/3 for terms that are
not further processed. Default:
false), add a full stop (.) to the output.
false), add a newline to the output.
- prepare_term(+Term, -Template, -Cycles, -Constraints)[private]
- Prepare a term, possibly holding cycles and constraints for
- infix_list(+Term, ?Op, -List) is semidet[private]
- True when List is a list of subterms of Term that are the result of
the nested infix operator Op. Deals both with
- pp_list_elements(+List, +Ctx, +Options) is det[private]
- Print the elements of a possibly open list as a vertical list.
- indent(+Out, +Indent, +Options)[private]
- Newline and indent to the indicated column. Respects the option
tab_width. Default is 8. If the tab-width equals zero,
indentation is emitted using spaces.
- print_width(+Term, -W, +Options) is det[private]
- Width required when printing `normally' left-to-right.
- pprint(+Term, +Context, +Options)[private]
- The bottom-line print-routine.
- is_op1(+Name, -Type, -Priority, -ArgPriority, +Options) is semidet[private]
- True if Name is an operator taking one argument of Type.
- is_op2(+Name, -LeftPri, -Pri, -RightPri, +Options) is semidet[private]
- True if Name is an operator taking two arguments of Type.
- need_space(@Term1, @Term2, +LeftOptions, +RightOptions)[private]
- True if a space is needed between Term1 and Term2 if they are
printed using the given option lists.
- end_code_type(+Term, -Code, Options)[private]
- True when code is the first/last character code that is emitted
by printing Term using Options.
- primitive(+Term, -Class) is semidet[private]
- True if Term is a primitive term, rendered using the CSS
- operator_module(-Module, +Options) is det[private]
- Find the module for evaluating operators.
- arg_options(+Options, -OptionsOut) is det[private]
- Increment depth in Options.