Links

• L-SIF Semantics
• L-SIF Examples
• L-SIF Applications

Contents

• Regular Expression Based Syntax Language Definition
• L-SIF Lexical Conventions and Tokens
• L-SIF Grammar
• Alphabetic Index of Grammar Nonterminals

Regular Expression Based Syntax Language Definition

This table provides a guideline as how to interpret the following two tables.
 

Syntax	Description
|	Or
*	Zero or more
+	One or more
[]	Optional subexpression
Comment Info	Appear in italics
Tokens	Appear in ALL CAPITALS
Key Words	Appear in bold

L-SIF Lexical Conventions and Tokens

L-SIF is an ASCII file format which is similar lexically to C code. L-SIF does not have a preprocessor, or any macro text facilities. It is a static scoped language, like Pascal.
 

Token	Description
{" ", "\t", "\n"}	White space is used as separators in L-SIF and then ignored
(* ... *)	Multiline comments can be nested
# ... \n	Single line comments can be used with multiline comments
( )	Delimit expression as in LISP
color	A color property
contour	A sequential set of closed 1D entities
desired_accuracy	The accuracy with which the designer wants the part manufactured
difference	A boolean difference operation
DECIMAL	Positive or negative decimal number
e	Exponential or Scientific notation for a value
inches	Sets units to inches
ID	C style identifier
INT	Positive or negative constant integer
intersection	A boolean intersection operation
layer	A planar cross section of the part
LSIF	Header stating that this is a L-SIF type file
mm	Sets units to millimeters
nested1d	A set of contours which are strictly nested inside a single outer contour
rgb	Specification of color as an rgb triple
thickness	Sets the thickness for layers within a scope
union	A boolean union operation
units	Sets the units for the file
v	A vertex

L-SIF Grammar

Nonterminal	->	Production
part_layers	->	( LSIF ver:INT rel:INT units accuracy thickness offset layer_list )
units	->	( units units_setting )
units_setting	->	mm | inches
accuracy	->	[ ( desired_accuracy value ) ]
thickness	->	( thickness value )
offset	->	( offset value )
layer_list	->	layer+
layer	->	( layer [ thickness ] vertex_list 1d_set* | contours_offset*)
1d_list	->	boolean | nested_1d
boolean	->	intersection | union | difference
intersection	->	( intersection 1d_list+ )
union	->	( union 1d_list+ )
difference	->	( difference 1d_list+ )
nested_1d	->	nested_1d_atom | contour
nested_1d_atom	->	( nested1d nested_1d_property vertex_list contour nested_1d )
contour	->	( contour contour_property vertex_list contour_segment_list )
contours_offset	->	contours offsets
contours	->	( contours nested_1d+ )
offsets	->	( offset nested_1d+ )
nested_1d_property	->	( color color_setting )
	|	(user extension)
contour_property	->	( color color_setting )
	|	(user extension)
contour_segment_list	->	id+
vertex_list	->	vertex*
vertex	->	( v id x:value y: value )
color_setting	->	( rgb R:value G:value B:value )
id	->	INT
value	->	INT
	|	DECIMAL
	|	( e mantissa:INT exponent:INT )

Alphabetic Index of Grammar Nonterminals

1d_set, accuracy, boolean, color_setting, contour, contour_property, contour_segment_list, difference, id, intersection, layer, layer_list, nested_1d, nested_1d_property, part_layers, thickness, union, units, units_setting, value, vertex, vertex_list