build: Remove support for Guile 1.8.

* configure.ac: Remove "1.8" from 'GUILE_PKG'.
Remove 'HAVE_GUILE2' conditional.  Remove checks for (srfi srfi-34),
(srfi srfi-35), and (srfi srfi-37).
* guilec.am: Inline what was in HAVE_GUILE2 and remove the alternate.
* src/guile/skribilo/debug.scm (debug-item): Remove 'cond-expand' and
keep only the 'guile-2' variant.
* src/guile/skribilo/engine.scm (engine-loaded?): Likewise.
* src/guile/skribilo/lib.scm (&invocation-location, define-markup): Likewise.
* src/guile/skribilo/utils/syntax.scm (%skribilo-module-reader): Likewise.
* web/index.skb: Remove mention of 1.8.
* README: Likewise.

9 files changed, 54 insertions, 122 deletions

diff --git a/README b/README
index ea62741..d10f636 100644
--- a/README
+++ b/README
@@ -29,7 +29,7 @@ Requirements
 
 You need at least:
 
-  * GNU Guile >= 1.8.3 (2.0.x recommended)
+  * GNU Guile >= 2.0.x
     http://www.gnu.org/software/guile/
 
   * Guile-Reader >= 0.6
diff --git a/configure.ac b/configure.ac
index 73cbc21..26b063d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -45,28 +45,14 @@ AC_PROG_LN_S
 AC_PROG_MKDIR_P
 
 # Look for Guile.
-GUILE_PKG([2.2 2.0 1.8])
+GUILE_PKG([2.2 2.0])
 GUILE_PROGS
 GUILE_SITE_DIR
-AC_PATH_PROGS([GUILD], [guild guile-tools])
-
-# GNU Guile 2.0.x and its compiler.
-AM_CONDITIONAL([HAVE_GUILE2],
-  [test "x$GUILD" != "x" && \
-   "$GUILD" compile --help >/dev/null 2>&1])
+AC_PATH_PROGS([GUILD], [guild])
 
 # Need Guile-Reader.
 GUILE_MODULE_REQUIRED([system reader])
 
-# SRFI-34 is normally in Guile 1.8, but let's make sure.
-GUILE_MODULE_REQUIRED([srfi srfi-34])
-
-# Need SRFI-35, available in Guile >= 1.8.3.
-GUILE_MODULE_REQUIRED([srfi srfi-35])
-
-# Need SRFI-37, available in Guile >= 1.8.3.
-GUILE_MODULE_REQUIRED([srfi srfi-37])
-
 # Make sure we're not using the broken SRFI-35 from Guile-Lib <= 0.1.6.
 SKR_GUILE_SRFI_35_WORKS
 
diff --git a/guilec.am b/guilec.am
index 8fa3daf..3519d61 100644
--- a/guilec.am
+++ b/guilec.am
@@ -1,8 +1,4 @@
 
-# Compilation with Guile-VM's compiler (aka. Guile 2.x).
-
-if HAVE_GUILE2
-
 # XXX: This expression relies on a GNU extension.
 GOBJECTS = $(SOURCES:%.scm=%.go)
 
@@ -48,10 +44,3 @@ SUFFIXES += .go
 # for details.
 skr_install_go_files = install-nobase_nodist_guileobjectDATA
 $(skr_install_go_files): install-nobase_dist_moduleDATA
-
-else !HAVE_GUILE2
-
-nobase_dist_module_DATA = $(SOURCES) $(SOURCES_NOT_COMPILED)
-nobase_nodist_guileobject_DATA =
-
-endif !HAVE_GUILE2
diff --git a/src/guile/Makefile.am b/src/guile/Makefile.am
index 6599581..7001377 100644
--- a/src/guile/Makefile.am
+++ b/src/guile/Makefile.am
@@ -1,5 +1,5 @@
 # Copyright 2005, 2006, 2007, 2008, 2009, 2010, 2012,
-#   2015, 2018 Ludovic Courtès <ludo@gnu.org>
+#   2015, 2018, 2020 Ludovic Courtès <ludo@gnu.org>
 #
 # This file is part of Skribilo.
 #
@@ -95,15 +95,10 @@ nobase_nodist_module_DATA =			\
   skribilo/config.scm				\
   skribilo/utils/images.scm
 
-if HAVE_GUILE2
-
 nobase_nodist_guileobject_DATA +=		\
  skribilo/config.go				\
  skribilo/utils/images.go
 
-endif HAVE_GUILE2
-
-
 BUILT_SOURCES =					\
   skribilo/config.scm				\
   skribilo/utils/images.scm
diff --git a/src/guile/skribilo/debug.scm b/src/guile/skribilo/debug.scm
index f3da3b9..80ab952 100644
--- a/src/guile/skribilo/debug.scm
+++ b/src/guile/skribilo/debug.scm
@@ -1,6 +1,6 @@
 ;;; debug.scm  --  Debugging facilities.  -*- coding: iso-8859-1 -*-
 ;;;
-;;; Copyright 2005, 2006, 2009, 2012  Ludovic Court�s <ludo@gnu.org>
+;;; Copyright 2005, 2006, 2009, 2012, 2020  Ludovic Court�s <ludo@gnu.org>
 ;;; Copyright 2003, 2004  Erick Gallesio - I3S-CNRS/ESSI <eg@unice.fr>
 ;;;
 ;;; This file is part of Skribilo.
@@ -110,17 +110,9 @@
     (for-each (lambda (a) (display a (*debug-port*))) args)
     (newline (*debug-port*))))
 
-(cond-expand
- (guile-2
-  (define-syntax-rule (debug-item args ...)
-    (if (*debug-item?*)
-        (%do-debug-item args ...))))
- (else
-  (begin
-    ;; Work around Guile 1.8's broken macro support.
-    (export %do-debug-item)
-    (define-macro (debug-item . args)
-      `(if (*debug-item?*) (%do-debug-item ,@args))))))
+(define-syntax-rule (debug-item args ...)
+  (if (*debug-item?*)
+      (%do-debug-item args ...)))
 
 
 ;;;
diff --git a/src/guile/skribilo/engine.scm b/src/guile/skribilo/engine.scm
index b1df2ce..a9e5701 100644
--- a/src/guile/skribilo/engine.scm
+++ b/src/guile/skribilo/engine.scm
@@ -1,7 +1,7 @@
 ;;; engine.scm	-- Skribilo engines.
 ;;; -*- coding: iso-8859-1 -*-
 ;;;
-;;; Copyright 2005, 2007, 2008, 2009, 2010, 2018  Ludovic Court�s <ludo@gnu.org>
+;;; Copyright 2005, 2007, 2008, 2009, 2010, 2018, 2020  Ludovic Court�s <ludo@gnu.org>
 ;;; Copyright 2003, 2004  Erick Gallesio - I3S-CNRS/ESSI <eg@essi.fr>
 ;;;
 ;;;
@@ -278,14 +278,8 @@
 (define (engine-loaded? id)
   "Check whether engine @var{id} is already loaded."
   ;; Trick taken from `resolve-module' in `boot-9.scm'.
-  (cond-expand (guile-2
-                (nested-ref-module (resolve-module '() #f)
-                                   (engine-id->module-name id)))
-               (else
-                ;; This method works for 1.8 but is deprecated in 1.9/2.0 and
-                ;; doesn't work with 1.9.11 anyway.
-                (nested-ref the-root-module
-                            `(%app modules ,@(engine-id->module-name id))))))
+  (nested-ref-module (resolve-module '() #f)
+                     (engine-id->module-name id)))
 
 ;; A mapping of engine names to hooks.
 (define %engine-load-hook (make-hash-table))
diff --git a/src/guile/skribilo/lib.scm b/src/guile/skribilo/lib.scm
index 5543644..ef18bda 100644
--- a/src/guile/skribilo/lib.scm
+++ b/src/guile/skribilo/lib.scm
@@ -1,6 +1,6 @@
 ;;; lib.scm -- Utilities.                 -*- coding: iso-8859-1 -*-
 ;;;
-;;; Copyright 2005, 2007, 2009, 2012, 2013, 2016  Ludovic Court�s <ludo@gnu.org>
+;;; Copyright 2005, 2007, 2009, 2012, 2013, 2016, 2020  Ludovic Court�s <ludo@gnu.org>
 ;;; Copyright 2003, 2004  Erick Gallesio - I3S-CNRS/ESSI <eg@unice.fr>
 ;;;
 ;;;
@@ -109,60 +109,44 @@
 ;; keyword style, and a couple other differences handled by
 ;; `dsssl->guile-formals'.
 
-(cond-expand
- (guile-2
-  ;; On Guile 2.0, `define-markup' generates a macro for the markup, such
-  ;; that the macro captures its invocation source location using
-  ;; `current-source-location'.
-
-  (define-syntax-parameter &invocation-location
-    (identifier-syntax #f))
-
-  (define-syntax define-markup
-    (lambda (s)
-      (syntax-case s ()
-        ;; Note: Use a dotted pair for formals, to allow for dotted forms
-        ;; like: `(define-markup (foo x . rest) ...)'.
-        ((_ (name . formals) body ...)
-         (let ((formals  (map (lambda (s)
-                                (datum->syntax #'formals s))
-                              (dsssl->guile-formals (syntax->datum #'formals))))
-               (internal (symbol-append '% (syntax->datum #'name)
-                                        '-internal)))
-           (with-syntax ((internal/loc (datum->syntax #'name internal)))
-             #`(begin
-                 (define* (internal/loc loc #,@formals)
-                   (syntax-parameterize ((&invocation-location
-                                          (identifier-syntax loc)))
-                     body ...))
-                 (define-syntax name
-                   (lambda (s)
-                     (syntax-case s ()
-                       ((_ . args)
-                        #'(let ((loc (source-properties->location
+;; On Guile 2.0, `define-markup' generates a macro for the markup, such
+;; that the macro captures its invocation source location using
+;; `current-source-location'.
+
+(define-syntax-parameter &invocation-location
+  (identifier-syntax #f))
+
+(define-syntax define-markup
+  (lambda (s)
+    (syntax-case s ()
+      ;; Note: Use a dotted pair for formals, to allow for dotted forms
+      ;; like: `(define-markup (foo x . rest) ...)'.
+      ((_ (name . formals) body ...)
+       (let ((formals  (map (lambda (s)
+                              (datum->syntax #'formals s))
+                            (dsssl->guile-formals (syntax->datum #'formals))))
+             (internal (symbol-append '% (syntax->datum #'name)
+                                      '-internal)))
+         (with-syntax ((internal/loc (datum->syntax #'name internal)))
+           #`(begin
+               (define* (internal/loc loc #,@formals)
+                 (syntax-parameterize ((&invocation-location
+                                        (identifier-syntax loc)))
+                   body ...))
+               (define-syntax name
+                 (lambda (s)
+                   (syntax-case s ()
+                     ((_ . args)
+                      #'(let ((loc (source-properties->location
+                                    (current-source-location))))
+                          (internal/loc loc . args)))
+                     (_
+                      #'(lambda args
+                          (let ((loc (source-properties->location
                                       (current-source-location))))
-                            (internal/loc loc . args)))
-                       (_
-                        #'(lambda args
-                            (let ((loc (source-properties->location
-                                        (current-source-location))))
-                              (apply internal/loc loc args)))))))
-                 internal/loc                     ; mark it as used
-                 (export name)))))))))
-
- (else                                            ; Guile 1.8
-  ;; On Guile 1.8, a markup is a procedure.  Its invocation source location
-  ;; is captured by walking the stack, which is fragile.
-
-  (define-macro (define-markup bindings . body)
-    (let ((name (car bindings))
-          (opts (cdr bindings)))
-      `(define*-public ,(cons name (dsssl->guile-formals opts))
-         ;; Memorize the invocation location.  Note: the invocation depth
-         ;; passed to `invocation-location' was determined experimentally and
-         ;; may change as Guile changes (XXX).
-         (let ((&invocation-location (invocation-location 3)))
-           ,@body))))))
+                            (apply internal/loc loc args)))))))
+               internal/loc                     ; mark it as used
+               (export name))))))))
 
 
 ;;;
diff --git a/src/guile/skribilo/utils/syntax.scm b/src/guile/skribilo/utils/syntax.scm
index c771507..5c606fc 100644
--- a/src/guile/skribilo/utils/syntax.scm
+++ b/src/guile/skribilo/utils/syntax.scm
@@ -1,7 +1,7 @@
 ;;; syntax.scm  --  Syntactic candy for Skribilo modules. -*- coding: utf-8 -*-
 ;;;
 ;;; Copyright 2005, 2006, 2007, 2008, 2009, 2010, 2011,
-;;;   2012, 2016, 2018 Ludovic Courtès <ludo@gnu.org>
+;;;   2012, 2016, 2018, 2020 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;;
 ;;; This file is part of Skribilo.
@@ -56,15 +56,7 @@
 			 "")
 		     (G_ "unexpected character in Skribilo module"))
 		    chr)))
-
-         (cond-expand
-          (guile-2 '(reader/record-positions))
-          (else
-           ;; On Guile 1.8, don't record positions by default: this yields a
-           ;; nice read performance improvement.
-           (if (memq 'positions (debug-options))
-               (list 'reader/record-positions)
-               '())))))
+         '(reader/record-positions)))
 
 (define-macro (skribilo-module-syntax)
   "Install the syntax reader for Skribilo modules."
diff --git a/web/index.skb b/web/index.skb
index ef4cf62..78f1cd8 100644
--- a/web/index.skb
+++ b/web/index.skb
@@ -139,8 +139,8 @@ document generation tasks.  Technically, the Skribilo language/API is an
 embedded domain-specific language (EDSL), implemented ,(it [via])
 so-called ,(ref :url
 "http://www.haskell.org/haskellwiki/Embedded_domain_specific_language#Degree_of_embedding"
-:text [“deep embedding”]).  Skribilo uses ,(guile [GNU Guile]) 2.2, 2.0,
-or 1.8 as the underlying Scheme implementation.])
+:text [“deep embedding”]).  Skribilo uses ,(guile [GNU Guile]) 2.2 or 2.0
+as the underlying Scheme implementation.])
 
 
    (chapter :title [Features] :number #f :file #f
@@ -181,7 +181,7 @@ General Public Licence]), version 3 or later.  To use Skribilo,
 you need the following pieces of software:
 
 ,(itemize
-    (item [,(guile [GNU Guile]) 2.2.*, 2.0.*, or 1.8.3+;])
+    (item [,(guile [GNU Guile]) 2.2.* or 2.0.*;])
     (item [,(ref :url "http://www.nongnu.org/guile-reader/"
                :text [Guile-Reader]) 0.6 or later;])
     (item [either ,(lout [Lout]) (3.31 or later), ,(latex [LaTeX]), or