Fix expression evaluation problem. (bmad-sim#1729)

* Fix expression evaluation problem.

Author: DavidSagan

bmad/modules/bmad_struct.f90

@@ -2454,13 +2454,13 @@ module bmad_struct
 integer, parameter :: acosh$ = 54, atanh$ = 55, acoth$ = 56, min$ = 57, max$ = 58, modulo$ = 59
 integer, parameter :: root$ = 60, parens$ = 61, square_brackets$ = 62, curly_brackets$ = 63, func_parens$ = 64
 integer, parameter :: arrow$ = 65, equal$ = 66, colon$ = 67, double_colon$ = 68, compound$ = 69, function$ = 70
-integer, parameter :: vertical_bar$ = 71, blank$ = 72
+integer, parameter :: vertical_bar$ = 71, blank$ = 72, ampersand$ = 73
 
 ! Names beginning with "?!+" are place holders that will never match to anything in an expression string.
 ! Note: "min", "max", "rms" and "average" are not implemented in Bmad but is used by Tao.
 ! Note: "species" is a function and "species_const" is a specified species like "electron".
 
-character(20), parameter :: expression_op_name(72) = [character(20) :: '+', '-', '*', '/', &
+character(20), parameter :: expression_op_name(73) = [character(20) :: '+', '-', '*', '/', &
                                 '(', ')', '^', '-', '+', '', 'sin', 'cos', 'tan', &
                                 'asin', 'acos', 'atan', 'abs', 'sqrt', 'log', 'exp', 'ran', &
                                 'ran_gauss', 'atan2', 'factorial', 'int', 'nint', 'floor', 'ceiling', &
@@ -2469,7 +2469,7 @@ module bmad_struct
                                 '(', '?!+Arg Count', 'antiparticle', 'cot', 'sec', 'csc', 'sign', &
                                 'sinh', 'cosh', 'tanh', 'coth', 'asinh', 'acosh', 'atanh', 'acoth', 'min', &
                                 'max', 'modulo', 'root', '()', '[]', '{}', '()', '->', '=', ':', '::', 'compound', &
-                                '?!+Function', '|', ' ']
+                                '?!+Function', '|', ' ', '&']
 
 integer, parameter :: expression_eval_level(69) = [1, 1, 3, 3, 0, 0, 4, 2, 2, -1, &
               9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, &

bmad/modules/expression_mod.f90

@@ -36,8 +36,8 @@ module expression_mod
 ! 
 ! An expression string will be split on:
 !   Two character operators: "->", "::" 
-!   operators: +-*/^=:
-!   brackets: [](){}
+!   operators: + -  * / ^ = : &
+!   brackets: [] () {}
 !   comma: ,
 !
 ! Root node name is "root" and is of type root$
@@ -142,7 +142,7 @@ recursive subroutine parse_pass(parse_line, tree, err_flag, err_str, tree_name)
 !
 
 parsing_loop: do
-  call get_next_chunk (parse_line, word, ix_word, ' []+-*/()^,{}=:|', delim, delim_found)
+  call get_next_chunk (parse_line, word, ix_word, ' &[]+-*/()^,{}=:|', delim, delim_found)
   if (ix_word == 0 .and. .not. delim_found) then
     if (tree%type /= root$ .and. tree%type /= equal$) then
       call set_this_err('Mismatched brackets. Cannot find closing bracket for opening: ' // quote(tree%name(1:1)) // &
@@ -164,7 +164,7 @@ recursive subroutine parse_pass(parse_line, tree, err_flag, err_str, tree_name)
     if (do_combine) then
       cc = upcase(word(ix_word:ix_word))
       if (cc /= 'E' .and. cc /= 'D') do_combine = .false.
-      if (.not. is_integer(parse_line, delims = '+-*/()^,[]{}=:| ', ix_word = ixe)) do_combine = .false.
+      if (.not. is_integer(parse_line, delims = '&+-*/()^,[]{}=:| ', ix_word = ixe)) do_combine = .false.
 
       do i = 1, ix_word-1
         if (index('.0123456789', word(i:i)) == 0) do_combine = .false.
@@ -250,6 +250,7 @@ recursive subroutine node_markup_pass(tree, err_flag, err_str)
            'ANOMALOUS_MOMENT_OF', 'COTH', 'SINH', 'COSH', 'TANH', 'ACOTH', 'ASINH', 'SUM', &
            'AVERAGE', 'RMS')
     node%type = function$
+  case ('&');                    node%type = ampersand$
   case ('->');                   node%type = arrow$
   case ('*');                    node%type = times$
   case ('/');                    node%type = divide$
@@ -268,16 +269,24 @@ recursive subroutine node_markup_pass(tree, err_flag, err_str)
     node%type = plus$
     if (in == 1) then
       node%type = unary_plus$
-    elseif (index('+-*/^,', trim(tree%node(in-1)%name)) > 0) then
-      node%type = unary_plus$
+    else
+      select case(tree%node(in-1)%type)
+      case(constant$, variable$, func_parens$, parens$, square_brackets$, curly_brackets$)
+      case default
+        node%type = unary_plus$
+      end select
     endif
 
   case ('-')
     node%type = minus$
     if (in == 1) then
       node%type = unary_minus$
-    elseif (index('+-*/^,', trim(tree%node(in-1)%name)) > 0) then
-      node%type = unary_minus$
+    else
+      select case(tree%node(in-1)%type)
+      case(constant$, variable$, func_parens$, parens$, square_brackets$, curly_brackets$)
+      case default
+        node%type = unary_plus$
+      end select
     endif
 
   case default

regression_tests/tao_test/output.correct

@@ -8,6 +8,7 @@
 "max([-1,-2,-3]) + min(4,2,3) + sum(-3,-1.0e-1)" REL 1E-9 -2.1000000000E+00
 "atan2(1,2)" REL 1E-9  4.6364760900E-01
 "data::twiss.end[1]|model-design+1e-10" REL 1E-9  1.0000000000E-10
+"[1,2] - [3, lat::r.11[beginning&end->-0.5*l]]" REL 1E-9 -2.0000000000E+00  1.0000000000E+00
 "sum(abs(ele::sbend::b*[angle]))" REL 1E-9  6.9813170080E-01
 "spin-tune" ABS 4E-9 -1.5719006590E+05
 "Polarization Limit ST" REL 4E-9                    0.0000000000E+00

tao/code/tao_evaluate_expression_new.f90

@@ -231,23 +231,21 @@ recursive subroutine bmad_tree_to_tao_tree(tree, tao_tree, expression, err_flag)
 
 ! A variable or datume like "[email protected]|model" is split by the parser into an array of nodes.
 ! Needed is to combine the nodes
-
-split_variable = .false.
-do in = 1, n_node
-  node => tree%node(in)
-  select case (node%type)
-  case (colon$, double_colon$, vertical_bar$)
-    split_variable = .true.
-    exit
-  case (square_brackets$)   ! "abc[...]" is a var or datum. "abc + [...]" is not.
-    if (in == 1) cycle
-    select case (tree%node(in-1)%name)
-    case ('+', '-', '*', '/', '^')
-    case default
-      split_variable = .true.
+! Note: "abc[...]" is a var or datum. "abc + [...]" is not.
+
+select case (tree%type)
+case(square_brackets$, func_parens$, parens$, curly_brackets$)
+  split_variable = .false.
+case default
+  split_variable = (n_node > 1)
+  do in = 1, n_node
+    node => tree%node(in)
+    select case (node%type)
+    case (plus$, minus$, unary_plus$, unary_minus$, times$, divide$, power$, func_parens$)
+      split_variable = .false.
     end select
-  end select
-enddo
+  enddo
+end select
 
 if (split_variable) then
   allocate(tao_tree%node(1))

tao/code/tao_regression_test.f90

@@ -20,7 +20,7 @@ subroutine tao_regression_test()
 logical err
 
 character(200) excite_zero(3), veto
-character(60) :: expr(11) = [character(60):: &
+character(60) :: expr(12) = [character(60):: &
                   '[anomalous_moment_of(proton), mass_of(electron)]', &
                   '(46.5/anomalous_moment_of(proton))^2-pi', &
                   '[3,4] * [1]@ele::q1[k1]', &
@@ -31,6 +31,7 @@ subroutine tao_regression_test()
                   'max([-1,-2,-3]) + min(4,2,3) + sum(-3,-1.0e-1)', &
                   'atan2(1,2)', &
                   'data::twiss.end[1]|model-design+1e-10', &
+                  '[1,2] - [3, lat::r.11[beginning&end->-0.5*l]]', &
                   'sum(abs(ele::sbend::b*[angle]))'  ]
 
 !

tao/doc/cover-page.tex

@@ -2,7 +2,7 @@
 
 \begin{flushright}
 \large
-Revision: September 15, 2025 \\
+Revision: September 21, 2025 \\
 \end{flushright}
 
 \vfill

tao/doc/generate_tex_for_pipe_commands.py

@@ -1,15 +1,12 @@
 #!/usr/bin/env python3
 # coding: utf-8
 
-# # Generate documentation for Tao pipe commands.
-# This will auto-generate documentation for the tao pipe commands. 
-# It extracts a formatted comment above each case statement.
-
-# Note: To run tests, do the following:
-#   1) python generate_tex_for_pipe_commands.py   # Run this file
-#   2) cd to pytao directory
-#   3) python generate_interface_commands.py
-#   4) python run_tests.py
+# This script will:
+#   1) Generate documentation (pipe-interface-commands.tex) for the tao pipe commands. 
+#       This is done by extracting the formatted comment above each case statement in tao_pipe_cmd.f90.
+#   2) Generate the pipe-interface-commands.json file for use in testing.
+
+# Note: To run tests, see the documentation in the regression_tests/README.md file.
 
 import json
 import os

tao/doc/pipe-interface-commands.json

@@ -1,4 +1,4 @@
-% WARNING: this is automatically generated. DO NOT EDIT.
+% WARNING: THIS FILE IS AUTOMATICALLY GENERATED! DO NOT EDIT!
 
 %% pipe beam ------------------------------------
 \subsection{pipe beam}
@@ -805,17 +805,15 @@ \subsection{pipe ele:lord_slave}
 Output the lord/slave tree of an element.
 
 \begin{example}
-   pipe ele:lord_slave \{ele_id\}|\{which\}
+   pipe ele:lord_slave \{ele_id\}
 \end{example}
 \begin{verbatim}
 Where: 
   {ele_id} is an element name or index.
-  {which} is one of: "model", "base" or "design"
 
 Example:
-  pipe ele:lord_slave 3@1>>7|model
+  pipe ele:lord_slave 3@1>>7
 This gives lord and slave info on element number 7 in branch 1 of universe 3.
-Note: The lord/slave info is independent of the setting of {which}.
 
 The output is a number of lines.
 Each line gives information on an element (element index, etc.).
@@ -1379,6 +1377,36 @@ \subsection{pipe lat_param_units}
 
 \end{verbatim}
 
+%% pipe lord_control ------------------------------------
+\subsection{pipe lord_control}
+\index{pipe!lord_control}
+\label{p:lord.control}
+
+
+Output lord information for a given slave element.
+
+\begin{example}
+   pipe lord_control \{ele_id\}
+\end{example}
+\begin{verbatim}
+Where:
+  {ele_id} is the slave element.
+
+Example:
+  pipe lord_control 2@1>>q01w
+
+The output is a number of lines with each line giving the information:
+    Lord-index;Lord-name;Lord-type;Attribute-controlled;Control-expression;Value
+
+Note: The last three fields will only be non-blank for ramper, overlay and group lords with
+the value field being blank for rampers.
+
+Note: For control expressed as a set of knot points (as opposed to an expression),
+the control-expression will be "knots".
+
+Note: The Value field is the contribution to the slave attribute value due to the lord.
+\end{verbatim}
+
 %% pipe matrix ------------------------------------
 \subsection{pipe matrix}
 \index{pipe!matrix}
@@ -1853,6 +1881,36 @@ \subsection{pipe show}
   pipe show lattice -pipe
 \end{verbatim}
 
+%% pipe slave_control ------------------------------------
+\subsection{pipe slave_control}
+\index{pipe!slave_control}
+\label{p:slave.control}
+
+
+Output slave information for a given lord element.
+
+\begin{example}
+   pipe slave_control \{ele_id\}
+\end{example}
+\begin{verbatim}
+Where:
+  {ele_id} is the lord element.
+
+Example:
+  pipe slave_control 2@1>>q01w
+
+The output is a number of lines with each line giving the information:
+    Slave-branch;Slave-index;Slave-name;Slave-type;Attribute-controlled;Control-expression;Value
+
+Note: The last three fields will only be non-blank for ramper, overlay and group lords with
+the value field being blank for ramper lords.
+
+Note: For control expressed as a set of knot points (as opposed to an expression),
+the control-expression will be "knots".
+
+Note: The Value field is the contribution to the slave attribute value due to the lord.
+\end{verbatim}
+
 %% pipe space_charge_com ------------------------------------
 \subsection{pipe space_charge_com}
 \index{pipe!space_charge_com}