Further module system revamp (fix #659)

To import a module now use:

    # Import module.jq file:
    import "relative/path/to/module" as foo;

    # Use the module's defs as foo::<def-name>

To import a JSON file:

    # Read file.json:
    import "relative/path/to/file" as $foo;
    #
    # Use as $foo::foo

Using `-L` now drops the builtin library path and appends the requested
path to the empty array (or the result of an earlier `-L`).

Support for the `$JQ_LIBRARY_PATH` environment variable has been
removed.

tests/modules/a.jq

@@ -1,2 +1,2 @@
-module a {version:1.7};
+module {version:1.7};
 def a: "a";

tests/modules/c/c.jq

@@ -1,12 +1,14 @@
-module c {whatever:null};
-import a as foo;
-import d as d {search:"./"};
-import d {search:"./"};
-import e as e {search:"./../lib/jq"};
-import f as f {search:"./../lib/jq"};
+module {whatever:null};
+import "a" as foo;
+import "d" as d {search:"./"};
+import "d" as d2{search:"./"};
+import "e" as e {search:"./../lib/jq"};
+import "f" as f {search:"./../lib/jq"};
+import "data" as $d;
 def a: 0;
 def c:
-  if meh != d::meh then error("import into namespace doesn't work")
+  if $d::d[0] != {this:"is a test",that:"is too"} then error("data import is busted")
+  elif d2::meh != d::meh then error("import twice doesn't work")
   elif foo::a != "a" then error("foo::a didn't work as expected")
   elif d::meh != "meh" then error("d::meh didn't work as expected")
   elif e::bah != "bah" then error("e::bah didn't work as expected")

tests/run

@@ -159,7 +159,7 @@ if which seq > /dev/null 2>&1; then
         fi
 
         dd "if=tests/torture/input0.json" bs=$i count=1 2>/dev/null |
-            $VALGRIND ./jq -cn --stream -L "$mods" 'import streaming; tovalues(inputs)' > $d/out1 2>$d/err || true
+            $VALGRIND ./jq -cn --stream -L "$mods" 'import "streaming" as streaming; streaming::tovalues(inputs)' > $d/out1 2>$d/err || true
         if [ -n "$VALGRIND" ]; then
             grep '^==[0-9][0-9]*== ERROR SUMMARY: 0 errors' $d/err > /dev/null
         else
@@ -200,22 +200,22 @@ if [ `HOME="$mods" $VALGRIND $Q ./jq --debug-dump-disasm -n fg | grep '^[a-z]' |
     exit 1
 fi
 
-if ! $VALGRIND $Q ./jq -ner -L "$mods" 'import a as foo; import b as bar; import a; def fooa: foo::a; [fooa, bar::a, bar::b, foo::a, a] | . == ["a","b","c","a","a"]' > /dev/null; then
+if ! $VALGRIND $Q ./jq -ner -L "$mods" 'import "a" as foo; import "b" as bar; def fooa: foo::a; [fooa, bar::a, bar::b, foo::a] | . == ["a","b","c","a"]' > /dev/null; then
     echo "Module system appears to be broken" 1>&2
     exit 1
 fi
 
-if ! $VALGRIND $Q ./jq -ner -L "$mods" 'import c as foo; [foo::a, foo::c] | . == [0,"acmehbah"]' > /dev/null; then
+if ! $VALGRIND $Q ./jq -ner -L "$mods" 'import "c" as foo; [foo::a, foo::c] | . == [0,"acmehbah"]' > /dev/null; then
     echo "Module system appears to be broken" 1>&2
     exit 1
 fi
 
-if [ "`$VALGRIND $Q ./jq -cner -L "$mods" '\"c\" | modulemeta'`" != '{"whatever":null,"name":"c","deps":[{"as":"foo","name":"a"},{"search":"./","as":"d","name":"d"},{"search":"./","name":"d"},{"search":"./../lib/jq","as":"e","name":"e"},{"search":"./../lib/jq","as":"f","name":"f"}]}' ]; then
+if [ "`$VALGRIND $Q ./jq -cner -L "$mods" '\"c\" | modulemeta'`" != '{"whatever":null,"deps":[{"as":"foo","is_data":false,"relpath":"a"},{"search":"./","as":"d","is_data":false,"relpath":"d"},{"search":"./","as":"d2","is_data":false,"relpath":"d"},{"search":"./../lib/jq","as":"e","is_data":false,"relpath":"e"},{"search":"./../lib/jq","as":"f","is_data":false,"relpath":"f"},{"as":"d","is_data":true,"relpath":"data"}]}' ]; then
     echo "modulemeta builtin appears to be broken" 1>&2
     exit 1
 fi
     
-if $VALGRIND ./jq -ner -L "$mods" 'import syntaxerror; .' > $d/out 2>&1; then
+if $VALGRIND ./jq -ner -L "$mods" 'import "syntaxerror" as e; .' > $d/out 2>&1; then
     echo "Module system appears to be broken" 1>&2
     exit 1
 fi