0cc04eaa2a
Because some of our examples use
%C%_reccalc_SOURCES = %D%/parse.y
Automake ships parse.y and parse.c, and possibly parse.h when it
"understands" that there is one. This is not what we want: ship only
parser.y. Yet we still want to use Automake to compile the sources
from parser.y. The easiest seems to use
nodist_%C%_reccalc_SOURCES = %D%/parse.y
together with
dist_reccalc_DATA = %D%/parse.y %D%/scan.l %D%/Makefile %D%/README.md
which guarantees that parse.y is indeed shipped.
* examples/c/calc/local.mk, examples/c/lexcalc/local.mk,
* examples/c/reccalc/local.mk: Always use nodist_*SOURCES for parsers,
let the dist_*_DATA rules do their job.
Examples in C
This directory contains simple examples of Bison grammar files in C.
Some of them come from the documentation, which should be installed together with Bison. The URLs are provided for convenience.
rpcalc - Reverse Polish Notation Calculator
The first example is that of a simple double-precision Reverse Polish Notation calculator (a calculator using postfix operators). This example provides a good starting point, since operator precedence is not an issue.
Extracted from the documentation: "Reverse Polish Notation Calculator" https://www.gnu.org/software/bison/manual/html_node/RPN-Calc.html
calc - Simple Calculator
This example is slightly more complex than rpcalc: it features infix
operators (1 + 2, instead of 1 2 + in rpcalc), but it does so using a
unambiguous grammar of the arithmetic instead of using precedence
directives (%left, etc.).
mfcalc - Multi-Function Calculator
A more complete C example: a multi-function calculator. More complex than the previous example. Using precedence directives to support infix operators.
Extracted from the documentation: "Multi-Function Calculator: mfcalc". https://www.gnu.org/software/bison/manual/html_node/Multi_002dfunction-Calc.html
lexcalc - calculator with Flex and Bison
The calculator, redux. This time using a scanner generated by Flex.
reccalc - recursive calculator with Flex and Bison
The example builds on top of the previous one to provide a reentrant parser.
Such parsers can be called concurrently in different threads, or even
recursively. To demonstrate this feature, expressions in parentheses are
tokenized as strings, and then recursively parsed from the parser. So
(((1)+(2))*((3)+(4))) uses eight parsers, with a depth of four.