#! /bin/sh

# Copyright (C) 2020 Free Software Foundation, Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# Users may customize the behavior of readline, which might break our
# expected results.
INPUTRC=/dev/null
export INPUTRC

# Beware of portability issues of readline when not feeding it from a
# terminal.
#
# With recent versions of GNU Readline, input "1+2*3\n" gives
# "> 1+2*3\n7\n> \n"
#
# macOS' version does not display the prompt and does not repeat stdin
# on stdout, so input "1+2*3\n" gives "7\n" as output.  Let's try to
# cope with this.
#
# On OpenBSD 6.5 the prompt is displayed, but the input is not
# repeated (!).  So input "1+2*3\n" gives "> 7\n> \n" as output.
#
# On AIX, you get some escaping sequence before the prompt:
# "<ESC>[?1034h> 1+2*3".  It appears to pass the terminfo capability
# "smm", to put the terminal in "meta mode": as if the user had hit
# META.

echo >perfect '> 0
0
> '

echo >ok '0'
echo '0' | prog >effective

echo "checking for readline output..."
if diff perfect effective; then
    # Alles ist gut.
    strip_prompt=false
elif diff ok effective; then
    strip_prompt=true
else
    skip "this is not the GNU Readline we expect"
fi


cat >input <<EOF
1+2*3
EOF
run 0 '> 1+2*3
7
> '

cat >input <<EOF
(1+2) * 3
EOF
run 0  '> (1+2) * 3
9
> '
run -noerr 0 '> (1+2) * 3
9
> ' -p

cat >input <<EOF
a = 256
sqrt (a)
EOF
run 0 '> a = 256
256
> sqrt (a)
16
> '

cat >input <<EOF
a = .16
b = 10 ^ 2
sqrt (a * b)
EOF
run 0 '> a = .16
0.16
> b = 10 ^ 2
100
> sqrt (a * b)
4
> '

cat >input <<EOF
*
EOF
run 0 '> *
> ''
err: 1.1: syntax error: expected end of file or - or ( or exit or number or function etc., before *
err:     1 | *
err:       | ^'

# Underline long errors.
cat >input <<EOF
123 123456
EOF
run 0 '> 123 123456
> ''
err: 1.5-10: syntax error: expected end of file or + or - or * or / or ^ before number
err:     1 | 123 123456
err:       |     ^~~~~~'

cat >input <<EOF
1 + 2 * * 3
EOF
run 0 '> 1 + 2 * * 3
> ''
err: 1.9: syntax error: expected - or ( or number or function or variable before *
err:     1 | 1 + 2 * * 3
err:       |         ^'

cat >input <<EOF
1 / 0
EOF
run 0 '> 1 / 0
> ''
err: 1.1-5: error: division by zero'


## ---------------- ##
## Error recovery.  ##
## ---------------- ##

cat >input <<EOF
((1 ++ 2) ** 3)
(1 ++ 2) + (3 ** 4)
EOF
run 0 '> ((1 ++ 2) ** 3)
666
> (1 ++ 2) + (3 ** 4)
1332
> ''
err: 1.6: syntax error: expected - or ( or number or function or variable before +
err:     1 | ((1 ++ 2) ** 3)
err:       |      ^
err: 2.5: syntax error: expected - or ( or number or function or variable before +
err:     2 | (1 ++ 2) + (3 ** 4)
err:       |     ^
err: 2.16: syntax error: expected - or ( or number or function or variable before *
err:     2 | (1 ++ 2) + (3 ** 4)
err:       |                ^'

# The rule "( error )" should work even if there are no tokens between "(" and ")".
cat >input <<EOF
()
EOF
run 0 '> ()
666
> ''
err: 1.2: syntax error: expected - or ( or number or function or variable before )
err:     1 | ()
err:       |  ^'


cat >input <<EOF
100% + 10
EOF
run 0 '> 100% + 10
> ''
err: 1.4: syntax error: invalid character: %'

# Traces.  This allows to check the location of the error.  If we
# forget to map YYerror to YYUNDEF, error recovery enters an endless
# loop with this input.
cat >input <<EOF
(+_)
EOF
run 0 '> (+_)
666
> ''
err: Starting parse
err: Entering state 0
err: Stack now 0
err: Reading a token
err: Next token is token ( (1.1: )
err: Shifting token ( (1.1: )
err: Entering state 2
err: Stack now 0 2
err: Return for a new token:
err: Reading a token
err: Next token is token + (1.2: )
err: LAC: initial context established for +
err: LAC: checking lookahead +: Err
err: LAC: checking lookahead end of file: Err
err: LAC: checking lookahead +: Err
err: LAC: checking lookahead -: S1
err: LAC: checking lookahead *: Err
err: LAC: checking lookahead /: Err
err: LAC: checking lookahead ^: Err
err: LAC: checking lookahead (: S2
err: LAC: checking lookahead ): Err
err: LAC: checking lookahead =: Err
err: LAC: checking lookahead exit: Err
err: LAC: checking lookahead number: S4
err: LAC: checking lookahead function: S5
err: LAC: checking lookahead variable: S6
err: LAC: checking lookahead NEG: Err
err: 1.2: syntax error: expected - or ( or number or function or variable before +
err:     1 | (+_)
err:       |  ^
err: LAC: initial context discarded due to error recovery
err: Shifting token error (1.2: )
err: Entering state 10
err: Stack now 0 2 10
err: Next token is token + (1.2: )
err: LAC: initial context established for +
err: LAC: checking lookahead +: Err
err: Error: discarding token + (1.2: )
err: Error: popping token error (1.2: )
err: Stack now 0 2
err: LAC: initial context discarded due to error recovery
err: Shifting token error (1.2: )
err: Entering state 10
err: Stack now 0 2 10
err: Return for a new token:
err: 1.3: syntax error: invalid character: _
err: Reading a token
err: Error: popping token error (1.2: )
err: Stack now 0 2
err: Shifting token error (1.2-3: )
err: Entering state 10
err: Stack now 0 2 10
err: Next token is token invalid token (1.3: )
err: LAC: initial context established for invalid token
err: LAC: checking lookahead invalid token: Always Err
err: Error: discarding token invalid token (1.3: )
err: Error: popping token error (1.2-3: )
err: Stack now 0 2
err: LAC: initial context discarded due to error recovery
err: Shifting token error (1.2-3: )
err: Entering state 10
err: Stack now 0 2 10
err: Return for a new token:
err: Reading a token
err: Next token is token ) (1.4: )
err: Shifting token ) (1.4: )
err: Entering state 20
err: Stack now 0 2 10 20
err: Reducing stack by rule XX (line XXX):
err:    $1 = token ( (1.1: )
err:    $2 = token error (1.2-3: )
err:    $3 = token ) (1.4: )
err: -> $$ = nterm exp (1.1-4: 666)
err: Entering state 8
err: Stack now 0 8
err: Return for a new token:
err: Reading a token
err: Now at end of input.
err: LAC: initial context established for end of file
err: LAC: checking lookahead end of file: R2 G7 S14
err: Reducing stack by rule XX (line XXX):
err:    $1 = nterm exp (1.1-4: 666)
err: -> $$ = nterm input (1.1-4: )
err: Entering state 7
err: Stack now 0 7
err: Now at end of input.
err: Shifting token end of file (1.5: )
err: LAC: initial context discarded due to shift
err: Entering state 14
err: Stack now 0 7 14
err: Stack now 0 7 14
err: Cleanup: popping token end of file (1.5: )
err: Cleanup: popping nterm input (1.1-4: )' -p



## ------------ ##
## Completion.  ##
## ------------ ##

# From now on, the differences between versions of GNU Readline are
# too painful to try to cope with.
if $strip_prompt; then
  echo "SKIP: this is not the GNU Readline we expect"
  exit $status
fi

# On Windows10/MSYS2 the ^G coming from <tab> completion is not
# emitted the same way
# (https://lists.gnu.org/r/bug-bison/2020-05/msg00076.html).
echo "checking for kernel name... $(uname -s)"
case $(uname -s) in
  (MSYS*)
    echo "SKIP: this is Windows/MSYS"
    exit $status
    ;;
esac


# Check completion after an operator.
sed -e 's/\\t/	/g' >input <<EOF
(1+\t\t
EOF
run 0 '> (1+
(       -       atan    cos     exp     ln      number  sin     sqrt
> (1+
> ''
err: 1.4: syntax error: expected - or ( or number or function or variable before end of file
err:     1 | (1+
err:       |    ^'

# Check the completion of a word.
sed -e 's/\\t/	/g' >input <<EOF
(at\t\t
EOF
run 0 '> (atan ( ''
> ''
err: 1.9: syntax error: expected - or ( or number or function or variable before end of file
err:     1 | (atan ( ''
err:       |         ^'

# Check the completion at the very beginning.
sed -e 's/\\t/	/g' >input <<EOF
e\t\t
EOF
run -n 0 '> e
end of file  exit         exp          ''
> e
0
> ''
err: '

# Check that completion prints valid locations even when there is an error.
sed -e 's/\\t/	/g' >input <<EOF
1++\t
EOF
run -n 0 '> 1++ ''
> ''
err: 1.3: syntax error: expected - or ( or number or function or variable before +
err:     1 | 1++ ''
err:       |   ^
'

# And even when the error was recovered from.
sed -e 's/\\t/	/g' >input <<EOF
(1++2) + 3 +\t\t
EOF
run -n 0 '> (1++2) + 3 +  ''
> ''
err: 1.4: syntax error: expected - or ( or number or function or variable before +
err:     1 | (1++2) + 3 +  ''
err:       |    ^
err: 1.15: syntax error: expected - or ( or number or function or variable before end of file
err:     1 | (1++2) + 3 +  ''
err:       |               ^
'
