edubart / lpegrex Goto Github PK

-- Convert an AST into a human readable string.
function lpegrex.prettyast(node)
  local ss = {}
  ast2string(node '', ss) -- !!!  notice here I removed the comma between node and '' 
  ss[#ss+1] = indent..tostring(child)
  return table.concat(ss, '\n')
end

return lpegrex

lua examples/lua-ast.lua /home/mingo/dev/c/A_grammars/peg-dad/dad/lua-test-return.lua

Block
| FuncDef
| | DotIndex
| | | "prettyast"
| | | Id
| | | | "lpegrex"
| | -
| | | Id
| | | | "node"
| | Block
| | | VarDecl
| | | | -
| | | | | IdDecl
| | | | | | "ss"
| | | | -
| | | | | Table
| | | Call
| | | | -
| | | | | Call
| | | | | | -
| | | | | | | String
| | | | | | | | ""
| | | | | | Id
| | | | | | | "node"
| | | | | Id
| | | | | | "ss"
| | | | Id
| | | | | "ast2string"
| | | Assign
| | | | -
| | | | | KeyIndex
| | | | | | BinaryOp
| | | | | | | UnaryOp
| | | | | | | | "len"
| | | | | | | | Id
| | | | | | | | | "ss"
| | | | | | | "add"
| | | | | | | Number
| | | | | | | | 1
| | | | | | Id
| | | | | | | "ss"
| | | | -
| | | | | BinaryOp
| | | | | | Id
| | | | | | | "indent"
| | | | | | "concat"
| | | | | | Call
| | | | | | | -
| | | | | | | | Id
| | | | | | | | | "child"
| | | | | | | Id
| | | | | | | | "tostring"
| | | Return
| | | | -
| | | | | Call
| | | | | | -
| | | | | | | Id
| | | | | | | | "ss"
| | | | | | | String
| | | | | | | | "\n"
| | | | | | DotIndex
| | | | | | | "concat"
| | | | | | | Id
| | | | | | | | "table"
| Return
| | -
| | | Id
| | | | "lpegrex"

logical-AND-expression <--
  (inclusive-OR-expression op-logical-AND*) ~> foldleft
op-logical-AND:binary-op <==
  {'&&'} SKIP @inclusive-OR-expression

logical-OR-expression <--
  (logical-AND-expression op-logical-OR*) ~> foldleft
op-logical-OR:binary-op <==
  {`||`} @logical-AND-expression

-- lpegrex in lpeg
pattern         <- exp !.
exp             <- S (grammar / alternative)

alternative     <- seq ('/' S seq)*
seq             <- prefix*
prefix          <- '&' S prefix / '!' S prefix / suffix
suffix          <- primary S (([+*?] S
                            / '^' (
				[-+]? num  -- (exactly n / at (least / most) n repetitions
				/ '^' name -- Syntax of relabel module. The pattern p^l is equivalent to p + lpeglabel.T(l).
				)
                            / '->' S (string / pcap / name / num)  -- capture
                            / '=>' S name) S)* -- match time capture

primary         <- '(' exp  ')' S / string / keyword / class / defined
                 / '{:' (name ':')? exp ':}' S  -- (named or anonymous) group capture
                 / '=' name           -- back reference
                 / '@' exp   -- for throwing labels errors on failure of expected matches
                 / pcap
                 / '{~' exp '~}' S  -- substitution capture
                 / '{|' exp '|}' S  -- table capture
                 / '{' exp '}' S    -- simple capture
		 / '~?' S             -- optional capture
		 / '~>' S ( 'foldleft' / 'foldright' / 'rfoldleft' / 'rfoldright' / name ) S -- fold capture
		 / '$' (string / name / num / pcap)
                 / '.' S
                 / name S !(asttag / arrow )
                 / '<' S name '>' S    -- old-style non terminals
		 / '%{' S name '}' S   -- Syntax of relabel module. Equivalent to lpeglabel.T(l)

grammar         <- definition+
definition      <- name S asttag? arrow exp

class           <- '[' '^'? item (!']' item)* ']' S
item            <- defined / range / .
range           <- . '-' [^]]

S               <- (%s / '--' [^%nl]*)*   -- spaces and comments
name            <- [A-Za-z_]([A-Za-z0-9_] / '-' !'>' )* S
arrow           <- (  '<--'    -- rule
                    / '<=='    -- for rules that capture AST Nodes
		    / '<-|'    -- for rules that capture tables
		    / '<-'
		    ) S
num             <- [0-9]+ S
string          <- ('"' [^"]* '"' / "'" [^']* "'") S
defined         <- '%' name  -- pattern defs[name] or a pre-defined pattern
keyword         <- '`' [^`]+ '`' S  -- tokens/keywords with automatic skipping
asttag          <- ':' S name  -- Capture tagged node rule
pcap            <- '{}' S -- position capture

lua examples/c11-ast.lua inputs/namespaces.c
lua: ./parsers/c11.lua:672: syntax error: inputs/namespaces.c:9:6: Expected_;
    T: s.T = 2;
     ^
stack traceback:
	[C]: in function 'error'
	./parsers/c11.lua:672: in function 'parsers.c11'
	examples/c11-ast.lua:15: in main chunk
	[C]: in ?

// namespaces.c
typedef int S, T, U;
struct S { int T; };
union U { int x; };
void f(void) {
	// The following uses of S, T, U are correct, and have no
	// effect on the visibility of S, T, U as typedef names.
	struct S s = { .T = 1 };
	T: s.T = 2;
	union U u = { 1 };
	goto T;
	// S, T and U are still typedef names:
	S ss = 1; T tt = 1; U uu = 1;
}