C.1 Symbol Format

A symbol is nothing more than an abstract representation of an object, represented by a preproc:sym node in the symbol table (see Symbol Table), For some symbol \(\sigma\) describing some object \(\theta\), the following attributes are recognized:

name

Unique identifier of \(\sigma\). Required.

type

Type of object described by \(\sigma\). Multiple symbols of different types may share the same \(\theta\). Required.

desc

Human-readable description of \(\theta\). Required.

dim

Dimensions of \(\theta\) as an integer. See _symtable:str-to-dim#1 for supported strings. Required

dtype

Reference to some symbol describing the datatype of \(\sigma\), if applicable.

tex

TeX code used to render \(\sigma\) in a math block.

parent

Reference to a symbol from which \(\sigma\) is derived. For example, a cgen symbol would have the associated class as its parent.

extern

Whether \(\sigma\) is unresolved in the given context.

missing

If extern, a human-readable message describing \(\theta\). This is useful to display to the user on error when \(\sigma\) is the result of generated code (e.g. template expansion).

no-deps

When true, linker does not attempt to look up dependencies for this symbol. Otherwise, as a safeguard against compilation bugs, the linker will fail if a symbol is missing a dependency list.

allow-circular

Permit \(\sigma\) to be part of a cycle (see Dependency Graph). This is desirable for recursive functions, but should otherwise be avoided like the plague.

keep

Always link \(\sigma\), even if disjoint from the program’s dependency graph. This is marked for removal.¹¹

An attribute not marked as required may be omitted. If an implementation wishes to attach additional metadata to a symbol, it must use a different namespace.

function: xs:integer _symtable:str-to-dim (str as xs:string?)

xmlns:_symtable="http://www.lovullo.com/tame/symtable/_priv"

Convert a string dimension representation into an integer.

Standard dimensions are ‘scalar’ (0), ‘vector’ (1), and ‘matrix’ (2). If no value is provided, then ‘scalar’ is assumed. All unknown strings will yield a value of ‘-1’.¹²

Definition:

<function name="_symtable:str-to-dim"  as="xs:integer">
  <param name="str"  as="xs:string?" />

  <choose>
    <when test="empty( $str ) or ( $str = 'scalar' )">
      <sequence select="0" />
    </when>

    <when test="$str = 'vector'">
      <sequence select="1" />
    </when>

    <when test="$str = 'matrix'">
      <sequence select="2" />
    </when>

    <otherwise>
      <sequence select="-1" />
    </otherwise>
  </choose>
</function>