tclparser-8.1.tcl

来自「Linux下的MSN聊天程序源码」· TCL 代码 · 共 613 行 · 第 1/2 页

#	name='value'
#
# Arguments:
#	opts	parser options
#	attrs	attribute string given in a tag
#
# Results:
#	Returns a Tcl list representing the name-value pairs in the 
#	attribute string
#
#	A ">" occurring in the attribute list causes problems when parsing
#	the XML.  This manifests itself by an unterminated attribute value
#	and a ">" appearing the element text.
#	In this case return a three element list;
#	the message "unterminated attribute value", the attribute list it
#	did manage to parse and the remainder of the attribute list.

proc xml::tclparser::ParseAttrs {opts attrs} {

    set result {}

    while {[string length [string trim $attrs]]} {
	if {[regexp [::sgml::cl $::xml::Wsp]*($::xml::Name)[::sgml::cl $::xml::Wsp]*=[::sgml::cl $::xml::Wsp]*("|')([::sgml::cl ^<]*?)\\2(.*) $attrs discard attrName delimiter value attrs]} {
	    lappend result $attrName [NormalizeAttValue $opts $value]
	} elseif {[regexp [::sgml::cl $::xml::Wsp]*$::xml::Name[::sgml::cl $::xml::Wsp]*=[::sgml::cl $::xml::Wsp]*("|')[::sgml::cl ^<]*\$ $attrs]} {
	    return -code error [list {unterminated attribute value} $result $attrs]
	} else {
	    return -code error "invalid attribute list"
	}
    }

    return $result
}

# xml::tclparser::NormalizeAttValue --
#
#	Perform attribute value normalisation.  This involves:
#	. character references are appended to the value
#	. entity references are recursively processed and replacement value appended
#	. whitespace characters cause a space to be appended
#	. other characters appended as-is
#
# Arguments:
#	opts	parser options
#	value	unparsed attribute value
#
# Results:
#	Normalised value returned.

proc xml::tclparser::NormalizeAttValue {opts value} {

    # sgmlparser already has backslashes protected
    # Protect Tcl specials
    regsub -all {([][$])} $value {\\\1} value

    # Deal with white space
    regsub -all "\[$::xml::Wsp\]" $value { } value

    # Find entity refs
    regsub -all {&([^;]+);} $value {[NormalizeAttValue:DeRef $opts {\1}]} value

    return [subst $value]
}

# xml::tclparser::NormalizeAttValue:DeRef --
#
#	Handler to normalize attribute values
#
# Arguments:
#	opts	parser options
#	ref	entity reference
#
# Results:
#	Returns character

proc xml::tclparser::NormalizeAttValue:DeRef {opts ref} {

    switch -glob -- $ref {
	#x* {
	    scan [string range $ref 2 end] %x value
	    set char [format %c $value]
	    # Check that the char is legal for XML
	    if {[regexp [format {^[%s]$} $::xml::Char] $char]} {
		return $char
	    } else {
		return -code error "illegal character"
	    }
	}
	#* {
	    scan [string range $ref 1 end] %d value
	    set char [format %c $value]
	    # Check that the char is legal for XML
	    if {[regexp [format {^[%s]$} $::xml::Char] $char]} {
		return $char
	    } else {
		return -code error "illegal character"
	    }
	}
	lt -
	gt -
	amp -
	quot -
	apos {
	    array set map {lt < gt > amp & quot \" apos '}
	    return $map($ref)
	}
	default {
	    # A general entity.  Must resolve to a text value - no element structure.

	    array set options $opts
	    upvar #0 $options(entities) map

	    if {[info exists map($ref)]} {

		if {[regexp < $map($ref)]} {
		    return -code error "illegal character \"<\" in attribute value"
		}

		if {![regexp & $map($ref)]} {
		    # Simple text replacement
		    return $map($ref)
		}

		# There are entity references in the replacement text.
		# Can't use child entity parser since must catch element structures

		return [NormalizeAttValue $opts $map($ref)]

	    } elseif {[string compare $options(-entityreferencecommand) "::sgml::noop"]} {

		set result [uplevel #0 $options(-entityreferencecommand) [list $ref]]

		return $result

	    } else {
		return -code error "unable to resolve entity reference \"$ref\""
	    }
	}
    }
}

# xml::tclparser::ParseEntity --
#
#	Parse general entity declaration
#
# Arguments:
#	data	text to parse
#
# Results:
#	Tcl list containing entity declaration

proc xml::tclparser::ParseEntity data {
    set data [string trim $data]
    if {[regexp $::sgml::ExternalEntityExpr $data discard type delimiter1 id1 discard delimiter2 id2 optNDATA ndata]} {
	switch $type {
	    PUBLIC {
		return [list external $id2 $id1 $ndata]
	    }
	    SYSTEM {
		return [list external $id1 {} $ndata]
	    }
	}
    } elseif {[regexp {^("|')(.*?)\1$} $data discard delimiter value]} {
	return [list internal $value]
    } else {
	return -code error "badly formed entity declaration"
    }
}

# xml::tclparser::delete --
#
#	Destroy parser data
#
# Arguments:
#	name	parser object
#
# Results:
#	Parser data structure destroyed

proc xml::tclparser::delete name {
    upvar \#0 [namespace current]::$name parser
    catch {::sgml::ParserDelete $parser(-statevariable)}
    catch {unset parser}
    return {}
}

# xml::tclparser::get --
#
#	Retrieve additional information from the parser
#
# Arguments:
#	name	parser object
#	method	info to retrieve
#	args	additional arguments for method
#
# Results:
#	Depends on method

proc xml::tclparser::get {name method args} {
    upvar #0 [namespace current]::$name parser

    switch -- $method {

	elementdecl {
	    switch [llength $args] {

		0 {
		    # Return all element declarations
		    upvar #0 $parser(elementdecls) elements
		    return [array get elements]
		}

		1 {
		    # Return specific element declaration
		    upvar #0 $parser(elementdecls) elements
		    if {[info exists elements([lindex $args 0])]} {
			return [array get elements [lindex $args 0]]
		    } else {
			return -code error "element \"[lindex $args 0]\" not declared"
		    }
		}

		default {
		    return -code error "wrong number of arguments: should be \"elementdecl ?element?\""
		}
	    }
	}

	attlist {
	    if {[llength $args] != 1} {
		return -code error "wrong number of arguments: should be \"get attlist element\""
	    }

	    upvar #0 $parser(attlistdecls)

	    return {}
	}

	entitydecl {
	}

	parameterentitydecl {
	}

	notationdecl {
	}

	default {
	    return -code error "unknown method \"$method\""
	}
    }

    return {}
}

# xml::tclparser::ExternalEntity --
#
#	Resolve and parse external entity
#
# Arguments:
#	name	parser object
#	base	base URL
#	sys	system identifier
#	pub	public identifier
#
# Results:
#	External entity is fetched and parsed

proc xml::tclparser::ExternalEntity {name base sys pub} {
}

# xml::tclparser:: --
#
#	Reset a parser instance, ready to parse another document
#
# Arguments:
#	name	parser object
#
# Results:
#	Variables unset

proc xml::tclparser::reset {name} {
    upvar \#0 [namespace current]::$name parser

    # Has this parser object been properly initialised?
    if {![info exists parser] || \
	    ![info exists parser(-name)]} {
	return [create $name]
    }

    array set parser {
	-final 1
	depth 0
	leftover {}
    }

    foreach var {Entities ExtEntities PEntities ExtPEntities ElDecls AttlistDecls NotDecls} {
	catch {unset [namespace current]::${var}$name}
    }

    # Initialise entities with predefined set
    array set [namespace current]::Entities$name [array get ::sgml::EntityPredef]

    return {}
}