diff --git a/HISTORY.md b/HISTORY.md
index 47f5298..2ed6a2d 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -4,23 +4,26 @@ History of SixtyPical
 0.21
 ----
 
+*   A source file can be included in another source file
+    by means of the `include` directive.
+*   A routine can be declared `preserved`, which prevents a
+    compiler from omitting it from the final executable, even
+    if it determines it is not called by any other routine.
 *   The reference implementation constructs a callgraph and
     determines the set of routines which are not reachable
     (directly or indirectly) from `main`, with an eye to
     omitting them from the final executable.
-*   A routine can be declared `preserved`, which prevents a
-    compiler from omitting it from the final executable, even
-    if it determines it is not called by any other routine.
 *   Added `--prune-unreachable-routines` option, which causes
     the compiler to in fact omit routines determined to be
     unreachable as described above.
+*   Added `--include-path` option, which configures the list
+    of directories that are searched when a source file is
+    included with the `include` directive.
 *   Code generation now performs modest peephole optimization
     at the end of each routine.  This results in better code
     generation for constructs in tail position, notably
     tail optimization of `calls`, but also for `goto`s and
     `if` blocks at the end of a routine.
-*   The `dcc6502-adapter` test adapter was updated to conform
-    to the output of the latest version of `dcc6502`.
 
 0.20
 ----
diff --git a/TODO.md b/TODO.md
index 127c031..c1c39c0 100644
--- a/TODO.md
+++ b/TODO.md
@@ -31,14 +31,6 @@ For goodness sake, let the programmer say `'A'` instead of `65`.
 Not all computers think `'A'` should be `65`.  Allow the character set to be
 mapped.  Probably copy what Ophis does.
 
-### "Include" directives
-
-Search a searchlist of include paths.  And use them to make libraries of routines.
-
-One such library routine might be an `interrupt routine` type for various architectures.
-Since "the supervisor" has stored values on the stack, we should be able to trash them
-with impunity, in such a routine.
-
 ### Pointers into non-byte tables
 
 Right now you cannot get a pointer into a non-byte (for instance, word or vector) table.
diff --git a/bin/sixtypical b/bin/sixtypical
index 2a3f20d..b1420b4 100755
--- a/bin/sixtypical
+++ b/bin/sixtypical
@@ -26,11 +26,12 @@ from sixtypical.compiler import Compiler
 
 def process_input_files(filenames, options):
     symtab = SymbolTable()
+    include_path = options.include_path.split(':')
 
     programs = []
 
     for filename in options.filenames:
-        program = load_program(filename, symtab)
+        program = load_program(filename, symtab, include_path)
         if options.debug:
             print(symtab)
         programs.append(program)
@@ -137,6 +138,12 @@ if __name__ == '__main__':
              "Default: raw."
     )
 
+    argparser.add_argument(
+        "--include-path", "-I", type=str, metavar='PATH', default='.',
+        help="A colon-separated list of directories in which to look for "
+             "files which are included during `include` directives."
+    )
+
     argparser.add_argument(
         "--analyze-only",
         action="store_true",
diff --git a/eg/README.md b/eg/README.md
index eb4be82..615a8aa 100644
--- a/eg/README.md
+++ b/eg/README.md
@@ -3,11 +3,18 @@ in subdirectories by machine architecture.
 
 ### rudiments
 
-In the [rudiments](rudiments/) directory are programs which are not for
-any particular machine, but meant to demonstrate the features of SixtyPical.
-Some are meant to fail and produce an error message.  Others can run on
-any architecture where there is a routine at 65490 which outputs the value
-of the accumulator as an ASCII character.
+In the [rudiments](rudiments/) directory are programs which are
+meant to demonstrate the elementary features of SixtyPical, and
+to serve as manual integration test cases.
+
+These sources are portable across architectures.  They include
+architecture-dependent libraries to produce output.  Libraries
+for such are provided in the `include` directory in the root
+directory of the repository; make it is on the compiler's include
+search path.
+
+Some others of these sources are meant to fail and produce an error
+message when compiled.
 
 ### c64
 
diff --git a/eg/rudiments/add.60p b/eg/rudiments/add.60p
index 3c5a631..5174627 100644
--- a/eg/rudiments/add.60p
+++ b/eg/rudiments/add.60p
@@ -1,6 +1,7 @@
-// Include `support/${PLATFORM}.60p` before this source
 // Should print YY
 
+include "chrout.60p"
+
 word score
 
 define main routine
diff --git a/eg/rudiments/buffer.60p b/eg/rudiments/buffer.60p
index 18eb6d8..d5c3023 100644
--- a/eg/rudiments/buffer.60p
+++ b/eg/rudiments/buffer.60p
@@ -1,6 +1,7 @@
-// Include `support/${PLATFORM}.60p` before this source
 // Should print Y
 
+include "chrout.60p"
+
 byte table[2048] buf
 pointer ptr @ 254
 byte foo
diff --git a/eg/rudiments/call.60p b/eg/rudiments/call.60p
index eed32f3..a407204 100644
--- a/eg/rudiments/call.60p
+++ b/eg/rudiments/call.60p
@@ -1,6 +1,7 @@
-// Include `support/${PLATFORM}.60p` before this source
 // Should print AA
 
+include "chrout.60p"
+
 define print routine
   trashes a, z, n
 {
diff --git a/eg/rudiments/cmp-byte.60p b/eg/rudiments/cmp-byte.60p
index 21e1f7b..1d488f1 100644
--- a/eg/rudiments/cmp-byte.60p
+++ b/eg/rudiments/cmp-byte.60p
@@ -1,6 +1,7 @@
-// Include `support/${PLATFORM}.60p` before this source
 // Should print ENGGL
 
+include "chrout.60p"
+
 byte b
 
 define main routine
diff --git a/eg/rudiments/cmp-litword.60p b/eg/rudiments/cmp-litword.60p
index 5cf9793..66366b6 100644
--- a/eg/rudiments/cmp-litword.60p
+++ b/eg/rudiments/cmp-litword.60p
@@ -1,6 +1,7 @@
-// Include `support/${PLATFORM}.60p` before this source
 // Should print ENGGL
 
+include "chrout.60p"
+
 word w1
 
 define main routine
diff --git a/eg/rudiments/cmp-word.60p b/eg/rudiments/cmp-word.60p
index 853c08e..e5ff73c 100644
--- a/eg/rudiments/cmp-word.60p
+++ b/eg/rudiments/cmp-word.60p
@@ -1,6 +1,7 @@
-// Include `support/${PLATFORM}.60p` before this source
 // Should print ENGGL
 
+include "chrout.60p"
+
 word w1
 word w2
 
diff --git a/eg/rudiments/conditional.60p b/eg/rudiments/conditional.60p
index 66c0ea8..cbb4c53 100644
--- a/eg/rudiments/conditional.60p
+++ b/eg/rudiments/conditional.60p
@@ -1,7 +1,7 @@
-// Demonstrates vector tables.
-// Include `support/${PLATFORM}.60p` before this source
 // Should print YN
 
+include "chrout.60p"
+
 define main routine
   trashes a, x, y, z, n, c, v
 {
diff --git a/eg/rudiments/conditional2.60p b/eg/rudiments/conditional2.60p
index 0def82c..6709b61 100644
--- a/eg/rudiments/conditional2.60p
+++ b/eg/rudiments/conditional2.60p
@@ -1,6 +1,7 @@
-// Include `support/${PLATFORM}.60p` before this source
 // Should print YA
 
+include "chrout.60p"
+
 define main routine
   trashes a, x, y, z, n, c, v
 {
diff --git a/eg/rudiments/example.60p b/eg/rudiments/example.60p
index a374c6e..e6f0031 100644
--- a/eg/rudiments/example.60p
+++ b/eg/rudiments/example.60p
@@ -1,6 +1,8 @@
-// Include `support/${PLATFORM}.60p` and `support/stdlib.60p` before this source
 // Should print 01
 
+include "chrout.60p"
+include "prbyte.60p"
+
 byte lives
 
 define main routine
diff --git a/eg/rudiments/goto.60p b/eg/rudiments/goto.60p
index 1c8d9a9..1e57945 100644
--- a/eg/rudiments/goto.60p
+++ b/eg/rudiments/goto.60p
@@ -1,6 +1,7 @@
-// Include `support/${PLATFORM}.60p` before this source
 // Should print AB
 
+include "chrout.60p"
+
 define bar routine trashes a, z, n {
     ld a, 66
     call chrout
diff --git a/eg/rudiments/loop.60p b/eg/rudiments/loop.60p
index 6ccb445..b4c57fc 100644
--- a/eg/rudiments/loop.60p
+++ b/eg/rudiments/loop.60p
@@ -1,6 +1,7 @@
-// Include `support/${PLATFORM}.60p` before this source
 // Should print ABCDEFGHIJKLMNOPQRSTUVWXYZ
 
+include "chrout.60p"
+
 define main routine
   trashes a, y, z, n, c
 {
diff --git a/eg/rudiments/memloc.60p b/eg/rudiments/memloc.60p
index cb8bd5b..2baf8a8 100644
--- a/eg/rudiments/memloc.60p
+++ b/eg/rudiments/memloc.60p
@@ -1,6 +1,7 @@
-// Include `support/${PLATFORM}.60p` before this source
 // Should print AB
 
+include "chrout.60p"
+
 byte foo
 
 define print routine
diff --git a/eg/rudiments/nested-for.60p b/eg/rudiments/nested-for.60p
index 833f09d..c735d90 100644
--- a/eg/rudiments/nested-for.60p
+++ b/eg/rudiments/nested-for.60p
@@ -1,6 +1,7 @@
-// Include `support/${PLATFORM}.60p` before this source
 // Should print H (being ASCII 72 = 8 * 9)
 
+include "chrout.60p"
+
 // Increase y by 7, circuitously
 //
 define foo routine
diff --git a/eg/rudiments/print.60p b/eg/rudiments/print.60p
index 7589930..78ac6bb 100644
--- a/eg/rudiments/print.60p
+++ b/eg/rudiments/print.60p
@@ -1,6 +1,7 @@
-// Include `support/${PLATFORM}.60p` before this source
 // Should print A
 
+include "chrout.60p"
+
 define main routine
   inputs a
   trashes a, z, n
diff --git a/eg/rudiments/vector-table.60p b/eg/rudiments/vector-table.60p
index 0bead91..7b8e9b0 100644
--- a/eg/rudiments/vector-table.60p
+++ b/eg/rudiments/vector-table.60p
@@ -1,7 +1,9 @@
-// Demonstrates vector tables.
-// Include `support/${PLATFORM}.60p` before this source
 // Should print AABAB
 
+// Demonstrates vector tables.
+
+include "chrout.60p"
+
 vector routine
   trashes a, z, n
     print
diff --git a/eg/rudiments/vector.60p b/eg/rudiments/vector.60p
index b4b018c..7f0b38a 100644
--- a/eg/rudiments/vector.60p
+++ b/eg/rudiments/vector.60p
@@ -1,6 +1,7 @@
-// Include `support/${PLATFORM}.60p` before this source
 // Should print AB
 
+include "chrout.60p"
+
 vector routine
   trashes a, z, n
     print
diff --git a/eg/rudiments/word-table.60p b/eg/rudiments/word-table.60p
index 54babbc..9372700 100644
--- a/eg/rudiments/word-table.60p
+++ b/eg/rudiments/word-table.60p
@@ -1,6 +1,7 @@
-// Include `support/${PLATFORM}.60p` before this source
 // Should print YY
 
+include "chrout.60p"
+
 word one
 word table[256] many
 
diff --git a/eg/rudiments/support/c64.60p b/include/c64/chrout.60p
similarity index 100%
rename from eg/rudiments/support/c64.60p
rename to include/c64/chrout.60p
diff --git a/eg/rudiments/support/stdlib.60p b/include/stdlib/prbyte.60p
similarity index 100%
rename from eg/rudiments/support/stdlib.60p
rename to include/stdlib/prbyte.60p
diff --git a/eg/rudiments/support/vic20.60p b/include/vic20/chrout.60p
similarity index 100%
rename from eg/rudiments/support/vic20.60p
rename to include/vic20/chrout.60p
diff --git a/src/sixtypical/parser.py b/src/sixtypical/parser.py
index ce03244..cc35c2d 100644
--- a/src/sixtypical/parser.py
+++ b/src/sixtypical/parser.py
@@ -21,8 +21,9 @@ class ForwardReference(object):
 
 
 class Parser(object):
-    def __init__(self, symtab, text, filename):
+    def __init__(self, symtab, text, filename, include_path):
         self.symtab = symtab
+        self.include_path = include_path
         self.scanner = Scanner(text, filename)
         self.current_routine_name = None
 
@@ -100,7 +101,7 @@ class Parser(object):
         while self.scanner.consume('include'):
             filename = self.scanner.token
             self.scanner.scan()
-            program = load_program(filename, self.symtab)
+            program = load_program(filename, self.symtab, self.include_path)
             includes.append(program)
         while self.scanner.on('typedef', 'const'):
             if self.scanner.on('typedef'):
@@ -479,9 +480,14 @@ class Parser(object):
 # - - - -
 
 
-def load_program(filename, symtab):
+def load_program(filename, symtab, include_path):
+    import os
+    for include_dir in include_path:
+        if os.path.exists(os.path.join(include_dir, filename)):
+            filename = os.path.join(include_dir, filename)
+            break
     text = open(filename).read()
-    parser = Parser(symtab, text, filename)
+    parser = Parser(symtab, text, filename, include_path)
     program = parser.program()
     return program