util.h File Reference

Development and debugging utilities. More...

#include <stdint.h>
#include <stdio.h>

Include dependency graph for util.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Functions
void	rdesc_dump_cst (FILE *out, const struct rdesc *parser, void(*node_printer)(FILE *out, const struct rdesc_node *))
	Dumps the concrete syntax tree (CST) as a graphviz DOT graph.
void	rdesc_dump_bnf (FILE *out, const struct rdesc_grammar *grammar, const char *const tk_names[], const char *const nt_names[])
	Dumps the grammar in BNF format.
void	rdesc_flip_left (struct rdesc *parser, struct rdesc_node *parent, uint16_t child_index)
	Rotates a right-recursive concrete syntax tree into a left-recursive form.

Detailed Description

Development and debugging utilities.

This header provides tools for visualizing data structures in librdesc.

Function Documentation

rdesc_dump_bnf()

void rdesc_dump_bnf	(	FILE *	out,
		const struct rdesc_grammar *	grammar,
		const char *const	tk_names[],
		const char *const	nt_names[]
	)

Dumps the grammar in BNF format.

Prints all production rules in human-readable BNF format. (e.g.A ::= B / C)

Parameters

out	Output file stream.
grammar	Underlying grammar struct.
tk_names	The token name or literal representation (e.g., IDENT or +). Prefix with '@' to suppress automatic quote wrapping.
nt_names	The raw name of the nonterminal (e.g., expr). Angle brackets <> are added automatically.

rdesc_dump_cst()

void rdesc_dump_cst	(	FILE *	out,
		const struct rdesc *	parser,
		void(*)(FILE *out, const struct rdesc_node *)	node_printer
	)

Dumps the concrete syntax tree (CST) as a graphviz DOT graph.

Parameters

out	Output file stream.
parser	Parser to dump its root.
node_printer	Callback to print token and nonterminal names.

rdesc_flip_left()

void rdesc_flip_left	(	struct rdesc *	parser,
		struct rdesc_node *	parent,
		uint16_t	child_index
	)

Rotates a right-recursive concrete syntax tree into a left-recursive form.

Performs an in-place transformation of a subtree to convert right-associative nodes into left-associative ones. This is typically used as a post-processing step for grammars transformed by the rrr macro.

The function converts the structure represented by:

A  → β A'
A' → α A' / ε

into the left-recursive equivalent:

A  → A α / β

α and β may consist of multiple tokens or nonterminal nodes. CST connections are maintained to ensure valid destruction and traversal.

The node to be rotated cannot be the root of the entire parse tree, so parent cannot be NULL. This is because a match is considered complete if and only if all nonterminals complete their bodies; this condition cannot be met if the start symbol (the root) is a recursive nonterminal.

Parameters

parser	Pointer to the rdesc parser instance.
parent	The parent node of the subtree root being rotated.
child_index	The index of the target node (A) within the parent's child list.