Definition: grammar of the NCX language

Mon, 01 Jan 0001 00:00:00 +0000

The NCX language is defined as a formal grammar in Backus-Naur form (BNF). An NC program consists of blocks (lines) made up of cells of the form [KEYWORD:ADDRESS=VALUE].

Grammar

<program> ::= ( <block> <new-line> )+
<new-line> ::= "\n"
<block> ::= <cell>+
<cell> ::= "[" <content> "]"
<content> ::= <function> "=" <target>
<function> ::= <text> | <text> ":" <address>
<address> ::= <text>
<target> ::= <value> | <value> "," <target>
<value> ::= <text> | <decimal> | <integer>
<decimal> ::= <integer> "." <digits>
<integer> ::= <digits> | "-" <digits>
<digits> ::= <digit>+
<digit> ::= "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
<text> ::= <character>+
<character> ::= "A" ... "Z" | <digit> | "_" | "+"

The productions in detail

<program>: A program consists of one or more blocks, each terminated by a new line.
<block>: A block is a sequence of one or more cells and corresponds to one program line.
<cell>: The cell is the basic unit of a program. Each cell consists of content enclosed in square brackets […].
<content>: The content of a cell is made up of a function and a target, separated by an equals sign =.
<function>: The function specifies which action the cell performs. It consists either of text alone or of text followed by a colon : and an address.
<address>: The address is optional and is only used when the function requires one. It consists of text.
<target>: The target specifies what the function is applied to: a single value or a comma-separated list of values (e.g. INTERPO=ARC,CCW).
<value>: A value can be text, a decimal number or an integer.
<decimal>: A decimal number consists of an integer part and a fractional part, separated by a decimal point . (e.g. -22.543).
<integer>: An integer is a positive or negative whole number without decimal places; negative numbers start with a minus sign -.
<digits>: A sequence of one or more digits.
<text>: Text is a sequence of one or more characters.
<character>: A single character is an uppercase letter A–Z, a digit, the underscore _ or the plus sign + (e.g. in WORKPLANE=XY+Z). Spaces are not permitted.

Example

A block, here a clockwise arc with a center point, consists of several cells:

Specification of the NCX elements

Mon, 01 Jan 0001 00:00:00 +0000

Each element of the NCX language is written as one cell of the form [KEYWORD:ADDRESS=VALUE]: the keyword, an optional address and the value. The following overview documents all elements with their addresses, values and examples; where available, the corresponding conventional G or M command is given as well. The underlying grammar is described in the Definition.

Program

`PROGRAM`: Program

Defines the header data of an NC program: name, unit of measurement and an optional comment.

Examples: Fanuc G-code to NCX

Mon, 01 Jan 0001 00:00:00 +0000

The following examples show how typical Fanuc G-code blocks are converted into the NCX format, each with the source block and the corresponding NCX cells.

Not yet specified

The rows marked with * use radius programming as well as the extended cycle parameters CYCLE_DELAY, CYCLE_SURFACE_ALTITUDE and CYCLE_DEPTH_INCREMENT. These are not yet covered by the current specification. The language is still in development.

NCXchange: the neutral NC code intermediate format on CNC-Master

Definition: grammar of the NCX language

Grammar

The productions in detail

Example

Specification of the NCX elements

Program

PROGRAM: Program

Examples: Fanuc G-code to NCX

`PROGRAM`: Program