C++ Mathematical Expression Library (ExprTk) http://www.partow.net/programming/exprtk/index.html
diff --git a/exprtk.hpp b/exprtk.hpp index a3d14ea..b4d4343 100644 --- a/exprtk.hpp +++ b/exprtk.hpp
@@ -23810,7 +23810,10 @@ default : return; } - parser_->dec_.add_assignment(symbol_name,cst); + if (!symbol_name.empty()) + { + parser_->dec_.add_assignment(symbol_name,cst); + } } inline expression_node_ptr synthesize_assignment_expression(const details::operator_type& operation, expression_node_ptr (&branch)[2])
diff --git a/readme.txt b/readme.txt index 1c29569..43c831b 100644 --- a/readme.txt +++ b/readme.txt
@@ -403,17 +403,17 @@ | | in the event they have fractional components truncation | | | will be performed. (eg: 1.67 --> 1) | +----------+---------------------------------------------------------+ -| := | Assign the value of x to y. Where x is a mutable string | -| | or string range and y is either a string or a string | +| := | Assign the value of x to y. Where y is a mutable string | +| | or string range and x is either a string or a string | | | range. eg: | -| | 1. x := y | -| | 2. x := 'abc' | -| | 3. x := y[:i + j] | -| | 4. x := '0123456789'[2:7] | -| | 5. x := '0123456789'[2i + 1:7] | -| | 6. x := (y := '0123456789'[2:7]) | -| | 7. x[i:j] := y | -| | 8. x[i:j] := (y + 'abcdefg'[8 / 4:5])[m:n] | +| | 1. y := x | +| | 2. y := 'abc' | +| | 3. y := x[:i + j] | +| | 4. y := '0123456789'[2:7] | +| | 5. y := '0123456789'[2i + 1:7] | +| | 6. y := (x := '0123456789'[2:7]) | +| | 7. y[i:j] := x | +| | 8. y[i:j] := (x + 'abcdefg'[8 / 4:5])[m:n] | | | | | | Note: For options 7 and 8 the shorter of the two ranges | | | will denote the number characters that are to be copied.| @@ -593,7 +593,7 @@ | | 2. max_size := max(v0[],v1[],v2[],v3[]) | +----------+---------------------------------------------------------+ -Note: In the above tables, the symbols x, y, z, w, u and v where +Note: In the tables above, the symbols x, y, z, w, u and v where appropriate may represent any of one the following: 1. Literal numeric/string value @@ -1307,10 +1307,10 @@ }; -In the above example, the input 'parameters' to the function operator, +In the example above, the input 'parameters' to the function operator, parameter_list_t, is a type of std::vector of type_store. Each type_store instance has a member called 'type' which holds the -enumeration pertaining the underlying type of the type_store. There +enumeration pertaining to the underlying type of the type_store. There are three type enumerations: (1) e_scalar - literals, variables, vector elements, expressions @@ -1570,7 +1570,7 @@ }; -In the above example there are four distinct parameter sequences that +In the example above there are four distinct parameter sequences that can be processed by the generic function 'roo'. Any other parameter sequences will cause a compilation error. The four valid sequences are as follows: @@ -2039,7 +2039,7 @@ parser.compile("1 + sin(30)",expression); -In the above example, the custom 'sin' function is registered with the +In the example above, the custom 'sin' function is registered with the symbol_table using the method 'add_reserved_function'. This is done so as to bypass the checks for reserved words that are carried out on the provided symbol names when calling the standard 'add_function' method. @@ -2261,9 +2261,10 @@ (06) All reserved words, keywords, variable, vector, string and function names are case-insensitive. - (07) Variable, vector and function names must begin with a letter - (A-Z or a-z), then can be comprised of any combination of - letters, digits and underscores. (eg: x, var1 or power_func99) + (07) Variable, vector, string variable and function names must begin + with a letter (A-Z or a-z), then can be comprised of any + combination of letters, digits and underscores. (eg: x, var1 or + power_func99) (08) Expression lengths and sub-expression lists are limited only by storage capacity.