Initial population.

1 files changed, 151 insertions, 0 deletions

diff --git a/src/hyper/pages/SYMBOL.ht b/src/hyper/pages/SYMBOL.ht
new file mode 100644
index 00000000..da25d20c
--- /dev/null
+++ b/src/hyper/pages/SYMBOL.ht
@@ -0,0 +1,151 @@
+% Copyright The Numerical Algorithms Group Limited 1992-94. All rights reserved.
+% !! DO NOT MODIFY THIS FILE BY HAND !! Created by ht.awk.
+\newcommand{\SymbolXmpTitle}{Symbol}
+\newcommand{\SymbolXmpNumber}{9.79}
+%
+% =====================================================================
+\begin{page}{SymbolXmpPage}{9.79 Symbol}
+% =====================================================================
+\beginscroll
+ 
+Symbols are one of the basic types manipulated by \Language{}.
+The \spadtype{Symbol} domain provides ways to create
+symbols of many varieties.
+\showBlurb{Symbol}
+ 
+\xtc{
+The simplest way to create a symbol is to ``single quote'' an identifier.
+%-% \HDindex{quote}{SymbolXmpPage}{9.79}{Symbol}
+}{
+\spadpaste{X: Symbol := 'x \bound{X}}
+}
+\xtc{
+This gives the symbol even if \spad{x} has been assigned a value.
+If \spad{x} has not been assigned a value, then it is possible to omit
+the quote.
+}{
+\spadpaste{XX: Symbol := x}
+}
+\xtc{
+Declarations must be used when working
+with symbols, because otherwise the interpreter tries to place
+values in a more specialized type \spadtype{Variable}.
+}{
+\spadpaste{A := 'a}
+}
+\xtc{
+}{
+\spadpaste{B := b}
+}
+\xtc{
+The normal way of entering polynomials uses this fact.
+}{
+\spadpaste{x**2 + 1}
+}
+ 
+\xtc{
+Another convenient way to create symbols is to convert a string.
+This is useful when the name is to be constructed by a program.
+}{
+\spadpaste{"Hello"::Symbol}
+}
+\xtc{
+Sometimes it is necessary to generate new unique symbols, for example, to
+name constants of integration.
+The expression \spad{new()} generates a symbol starting with \spad{\%}.
+}{
+\spadpaste{new()\$Symbol}
+}
+\xtc{
+Successive calls to \spadfunFrom{new}{Symbol} produce different symbols.
+}{
+\spadpaste{new()\$Symbol}
+}
+\xtc{
+The expression \spad{new("s")} produces a symbol starting with \spad{\%s}.
+}{
+\spadpaste{new("xyz")\$Symbol}
+}
+ 
+\xtc{
+A symbol can be adorned in various ways.
+The most basic thing is applying a symbol to a list
+of subscripts.
+}{
+\spadpaste{X[i,j] \free{X}}
+}
+ 
+\xtc{
+Somewhat less pretty is to attach subscripts, superscripts or arguments.
+}{
+\spadpaste{U := subscript(u, [1,2,1,2]) \bound{U}}
+}
+\xtc{
+}{
+\spadpaste{V := superscript(v, [n]) \bound{V}}
+}
+\xtc{
+}{
+\spadpaste{P := argscript(p, [t]) \bound{P}}
+}
+ 
+\xtc{
+It is possible to test whether a symbol has scripts using the
+\spadfunFrom{scripted?}{Symbol} test.
+}{
+\spadpaste{scripted? U \free{U}}
+}
+\xtc{
+}{
+\spadpaste{scripted? X \free{X}}
+}
+\xtc{
+If a symbol is not scripted, then it may be converted to a string.
+}{
+\spadpaste{string X \free{X}}
+}
+\xtc{
+The basic parts can always be extracted using the
+\spadfunFrom{name}{Symbol} and \spadfunFrom{scripts}{Symbol} operations.
+}{
+\spadpaste{name U \free{U}}
+}
+\xtc{
+}{
+\spadpaste{scripts U \free{U}}
+}
+\xtc{
+}{
+\spadpaste{name X \free{X}}
+}
+\xtc{
+}{
+\spadpaste{scripts X \free{X}}
+}
+ 
+\xtc{
+The most general form is obtained using the \spadfunFrom{script}{Symbol}
+operation.
+This operation takes an argument which is a list containing, in this order,
+lists of subscripts, superscripts, presuperscripts, presubscripts and
+arguments to a symbol.
+}{
+\spadpaste{M := script(Mammoth, [[i,j],[k,l],[0,1],[2],[u,v,w]]) \bound{M}}
+}
+\xtc{
+}{
+\spadpaste{scripts M \free{M}}
+}
+\xtc{
+If trailing lists of scripts are omitted, they are assumed to be empty.
+}{
+\spadpaste{N := script(Nut, [[i,j],[k,l],[0,1]]) \bound{N}}
+}
+\xtc{
+}{
+\spadpaste{scripts N \free{N}}
+}
+\endscroll
+\autobuttons
+\end{page}
+%