X-Git-Url: http://nitlanguage.org

diff --git a/src/parser_util.nit b/src/parser_util.nit
index f9ea467..cd4f205 100644
--- a/src/parser_util.nit
+++ b/src/parser_util.nit
@@ -15,7 +15,7 @@
 # Utils and tools related to parsers and AST
 module parser_util
 
-import parser
+intrude import parser
 import toolcontext
 
 redef class ToolContext
@@ -30,7 +30,7 @@ redef class ToolContext
 
 		var eof = tree.n_eof
 		if eof isa AError then
-			self.fatal_error(null, "Fatal Error: {eof.message}")
+			self.fatal_error(null, "Fatal Error: {eof.message}.")
 			abort
 		end
 		return tree.n_base.as(not null)
@@ -43,7 +43,7 @@ redef class ToolContext
 		var nmodule = parse_module(string)
 		var nclassdefs = nmodule.n_classdefs
 		if nclassdefs.length != 1 then
-			self.fatal_error(null, "Fatal Error: not a classdef")
+			self.fatal_error(null, "Fatal Error: not a classdef.")
 			abort
 		end
 		return nclassdefs.first
@@ -57,7 +57,7 @@ redef class ToolContext
 		var nclassdef = parse_classdef(mod_string)
 		var npropdefs = nclassdef.n_propdefs
 		if npropdefs.length != 1 then
-			self.fatal_error(null, "Fatal Error: not a propdef")
+			self.fatal_error(null, "Fatal Error: not a propdef.")
 			abort
 		end
 		return npropdefs.first
@@ -69,7 +69,7 @@ redef class ToolContext
 	do
 		var mod_string = "do\n{string}\nend"
 		var nmodule = parse_module(mod_string)
-		var nblock = nmodule.n_classdefs.first.n_propdefs.first.as(AMainMethPropdef).n_block.as(ABlockExpr).n_expr.first.as(ADoExpr).n_block.as(not null)
+		var nblock = nmodule.n_classdefs.first.n_propdefs.first.as(AMethPropdef).n_block.as(ABlockExpr).n_expr.first.as(ADoExpr).n_block.as(not null)
 		return nblock
 	end
 
@@ -79,30 +79,175 @@ redef class ToolContext
 	do
 		var mod_string = "var dummy = \n{string}"
 		var nmodule = parse_module(mod_string)
-		var nexpr = nmodule.n_classdefs.first.n_propdefs.first.as(AMainMethPropdef).n_block.as(ABlockExpr).n_expr.first.as(AVardeclExpr).n_expr.as(not null)
+		var nexpr = nmodule.n_classdefs.first.n_propdefs.first.as(AMethPropdef).n_block.as(ABlockExpr).n_expr.first.as(AVardeclExpr).n_expr.as(not null)
 		return nexpr
 	end
-end
 
-redef class ANode
-	# Return an array of tokens that match a given text
-	fun collect_tokens_by_text(text: String): Array[Token]
+	# Parse a super class declaration
+	# Fatal error if the `string` is not a syntactically correct super class declaration
+	fun parse_superclass(string: String): APropdef
+	do
+		var mod_string = "class Dummy\nsuper {string}\nend"
+		var nclassdef = parse_classdef(mod_string).as(AStdClassdef)
+		var nsuperclasses = nclassdef.n_propdefs
+		if nsuperclasses.length != 1 then
+			self.fatal_error(null, "Fatal Error: not a super class declaration.")
+			abort
+		end
+		return nsuperclasses.first
+	end
+
+	# Try to parse the `string` as something
+	#
+	# Returns the first possible syntacticaly correct type among:
+	#
+	# - a type `AType`
+	# - a single `Token`
+	# - an expression `AExpr`
+	# - a block of statements `ABlockExpr`
+	# - a full module `AModule`
+	# - a `AError` if nothing else matches
+	#
+	#     var tc = new ToolContext
+	#     assert tc.parse_something("foo") isa TId
+	#     assert tc.parse_something("foo[bar]") isa AExpr
+	#     assert tc.parse_something("Foo[Bar]") isa AType
+	#     assert tc.parse_something("foo\nbar") isa ABlockExpr
+	#     assert tc.parse_something("fun foo do bar\nfoo") isa AModule
+	#     assert tc.parse_something("fun fun") isa AParserError
+	#     assert tc.parse_something("?%^&") isa ALexerError
+	fun parse_something(string: String): ANode
+	do
+		var source = new SourceFile.from_string("", string)
+		var error
+		var tree
+		var eof
+		var lexer
+
+		lexer = new InjectedLexer(source)
+		lexer.injected_before.add new TKwvar
+		lexer.injected_before.add new TId
+		lexer.injected_before.add new TColumn
+		lexer.injected_before.add new TClassid
+		lexer.injected_before.add new TObra
+		lexer.injected_after.add new TCbra
+		tree = (new Parser(lexer)).parse
+		eof = tree.n_eof
+		if not eof isa AError then
+			var ntype = tree.n_base.n_classdefs.first.n_propdefs.first.as(AMethPropdef).n_block.as(ABlockExpr).n_expr.first.as(AVardeclExpr).n_type.n_types.first
+			ntype.parent = null
+			return ntype
+		end
+		error = eof
+
+		lexer = new Lexer(source)
+		var first = lexer.next
+		if first isa EOF then return first
+		var second = lexer.next
+		if second isa EOF and not second isa AError then
+			first.parent = null
+			return first
+		end
+
+		lexer = new InjectedLexer(source)
+		lexer.injected_before.add new TKwvar
+		lexer.injected_before.add new TId
+		lexer.injected_before.add new TAssign
+		lexer.injected_before.add new TOpar
+		lexer.injected_after.add new TCpar
+		tree = (new Parser(lexer)).parse
+		eof = tree.n_eof
+		if not eof isa AError then
+			var nexpr = tree.n_base.n_classdefs.first.n_propdefs.first.as(AMethPropdef).n_block.as(ABlockExpr).n_expr.first.as(AVardeclExpr).n_expr.as(AParExpr).n_expr
+			nexpr.parent = null
+			return nexpr
+		end
+		if eof.location > error.location then error = eof
+
+		lexer = new InjectedLexer(source)
+		lexer.injected_before.add new TKwdo
+		lexer.injected_before.add new TEol
+		lexer.injected_after.add new TEol
+		lexer.injected_after.add new TKwend
+		tree = (new Parser(lexer)).parse
+		eof = tree.n_eof
+		if not eof isa AError then
+			var nblock = tree.n_base.n_classdefs.first.n_propdefs.first.as(AMethPropdef).n_block.as(ABlockExpr).n_expr.first.as(ADoExpr).n_block.as(ABlockExpr)
+			nblock.n_kwend = null # drop injected token
+			nblock.parent = null
+			return nblock
+		end
+		if eof.location > error.location then error = eof
+
+		lexer = new Lexer(source)
+		tree = (new Parser(lexer)).parse
+		eof = tree.n_eof
+		if not eof isa AError then
+			return tree.n_base.as(not null)
+		end
+		if eof.location > error.location then error = eof
+
+		return error
+	end
+
+	# Parse the input of the user as something
+	fun interactive_parse(prompt: String): ANode
 	do
-		var v = new CollectTokensByTextVisitor(text)
-		v.enter_visit(self)
-		return v.result
+		var oldtext = ""
+
+		loop
+			printn prompt
+			printn " "
+			var s = sys.stdin.read_line
+			if s == "" then continue
+			if s.chars.first == ':' then
+				var res = new TString
+				res.text = s
+				return res
+			end
+
+			var text = oldtext + s + "\n"
+			oldtext = ""
+			var n = parse_something(text)
+
+			if n isa AParserError and n.token isa EOF then
+				# Unexpected end of file, thus continuing
+				if oldtext == "" then prompt = "." * prompt.length
+				oldtext = text
+				continue
+			end
+
+			return n
+		end
 	end
 end
 
-private class CollectTokensByTextVisitor
-	super Visitor
-	var text: String
-	init(text: String) do self.text = text
-	var result = new Array[Token]
-	redef fun visit(node)
+# A modified lexer that feed tokens before and after the real tokens.
+class InjectedLexer
+	super Lexer
+
+	# The tokens to use before the real tokens (in order).
+	var injected_before = new List[Token]
+
+	# The tokens to use after the real tokens (in order).
+	# The real EOF token is produced after these tokens.
+	var injected_after = new List[Token]
+	private var is_finished = false
+
+	redef fun get_token
 	do
-		if node == null then return
-		node.visit_all(self)
-		if node isa Token and node.text == text then result.add(node)
+		if not injected_before.is_empty then
+			var tok = injected_before.shift
+			return tok
+		end
+		if not is_finished then
+			var next = super
+			if not next isa EOF then return next
+			injected_after.push(next)
+			is_finished = true
+		end
+
+		var tok = injected_after.shift
+		return tok
 	end
 end