doc (Core Concepts): Initial stub section

I wanted to get this section started so that I can easily add to it when I
have small bits of time to do so.  Our documentation needs to improve.

* doc/Makefile.am (tame_TEXINFOS): Add `concept.texi'.
* doc/concept.texi: New file.
* doc/preproc.texi: Remove accidentally added input line.
* doc/tame.texi (menu): Add `Core Concepts' node.

doc/Makefile.am

@@ -27,8 +27,8 @@ stylesheets := $(shell find "$(path_src)" \
 stexi       := $(stylesheets:.xsl=.texi)
 
 info_TEXINFOS = tame.texi
-tame_TEXINFOS = usage.texi macros.texi preproc.texi license.texi \
-                config.texi $(stexi) tame.css
+tame_TEXINFOS = usage.texi concept.texi preproc.texi license.texi \
+                config.texi macros.texi $(stexi) tame.css
 
 MAKEINFOHTML=$(MAKEINFO) --html --css-include tame.css
 

doc/concept.texi

@@ -0,0 +1,67 @@
+@c  This document is part of the TAME manual.
+@c  Copyright (C) 2019 R-T Specialty, LLC.
+@c    Permission is granted to copy, distribute and/or modify this document
+@c    under the terms of the GNU Free Documentation License, Version 1.3 or
+@c    any later version published by the Free Software Foundation; with no
+@c    Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
+@c    A copy of the license is included in the section entitled ``GNU Free
+@c    Documentation License''.
+
+@node Core Concepts
+@chapter Core Concepts
+@helpwanted
+
+@cindex declarative, programming
+@cindex imperative, programming
+@tame is a @dfn{declarative} programming language@mdash{
+  }it @emph{describes} how a program ought to behave rather than
+    explicitly telling a computer the steps needed to make it work
+    (@dfn{imperative}).
+@tame is a calculator at heart,
+  so code written in its language describes mathematical operations.
+Definitions fall primarily under two categories:
+
+@table @strong
+  @cindex classifications
+  @item Classifications
+  Higher-order logic used to classify data and predicate calculations,
+    controlling program flow.
+
+  @cindex calculations
+  @item Calculations
+  Mathematical operations motivated by linear algebra.
+@end table
+
+@tame also supports abstracting calculations into @dfn{functions},
+  which permits the use of recursion for solving problems that are
+  difficult to fit into an algebraic model.
+The language is Turing-complete.
+
+@cindex metalanguage
+@cindex domain-specific language
+@tame itself is a @dfn{domain-specific language} (DSL)@mdash{
+  }it was designed for use in comparative insurance rating systems.
+However,
+  it couldn't possibly know all useful abstractions that may be needed
+    in the future;
+      the domain for which @tame was designed encompasses many
+      subdomains as well.
+To accommodate future needs,
+  @tame is also a @dfn{metalanguage}@mdash{
+    }a language that can be used to program itself.
+The core language is based upon broad mathematical foundations
+  that offer great flexibility.
+Its expressive template system allows the creation of abstractions
+  that are indistinguishable from core language features,
+    and templates have powerful introspective capabilities that allow
+    for many useful types of code generation.
+Essentially,
+  @tame allows the creation of sub-DSLs.
+
+Code is written in @tame without regard to order of execution@mdash{
+  }the linker will figure that out for you.
+This simplifies the development of systems with complex graphs of
+  dependencies.
+
+@todo{This chapter is a placeholder.
+      More to come.}

doc/preproc.texi

@@ -1,4 +1,3 @@
-\input texinfo
 @c  This document is part of the TAME manual.
 @c  Copyright (C) 2015, 2016, 2018, 2019 R-T Specialty, LLC.
 @c    Permission is granted to copy, distribute and/or modify this document

doc/tame.texi

@@ -63,6 +63,7 @@ Free Documentation License".
 
 @menu
 * Using TAME::        History of TAME and how to use it
+* Core Concepts::     Design philosophy and mathematical concepts
 * Preprocessor::      Metaprogramming system
 * Dependency Graph::  Dependency processing and flow analysis
 * Symbol Table::      Lookup table for all objects
@@ -79,6 +80,7 @@ Free Documentation License".
 
 
 @include usage.texi
+@include concept.texi
 @include preproc.texi
 
 @include src/graph.texi